Science Learning Packet CHEM A: Nuclear Chemistry Packet

science learning activities for SPS students during the COVID-19 school closure.

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Due to the COVID-19 closure, teachers were asked to provide packets of home activities. This is not intended to take the place of regular classroom instruction but will help supplement student learning and provide opportunities for student learning while they are absent from school. Assignments are not required or graded. Because of the unprecedented nature of this health crisis and the District’s swift closure, some home activities may not be accessible.

If you have difficulty accessing the material or have any questions, please contact your student’s teacher. CHEM A (Nuclear Science) Seattle Public Schools Science Learning Packet March 2020 INTRODUCTION: Take Home Unit – Nuclear Science

Nuclear science is a hotly debated area of research. Many people feel uncomfortable with nuclear energy because of how it has been used or famous meltdowns such as Chernobyl. The scientific community views nuclear research as the next step toward a sustainable future. Both sides of the debate have valid reasoning, but to participate fully, you must fully understand the science and arguments on both sides.

Throughout this unit, you will complete an activity or group of activities to understand different forms of nuclear change. You will then read a pro and con article about the effects of this type of nuclear change.

Why should you do this? The nuclear unit dives into two key standards that all high school students are expected to know by their Junior year. These two standards are not taught in any other science course in high school.

How can you do the labs? The nuclear unit has a few labs that are used to model different changes. 4.5a requires 15 marshmallows and 15 gummy bears. These can be replaced with any candies or items (candy is more fun because you can eat them!). You could also just use your imagination and draw the different atoms. 4.8a requires 50-100 pennies (or any item with two sides) and the same amount of paper clips (or another item to replace the pennies over time). Following the instructions should make it easy to complete. There is a video at the end of the assignment if you do not have materials. 4.4a and 4.7a both require java. Many home computers have java and you are able to download it onto your school computer, butit is difficult. There are linked videos as alternatives if you cannot get them to work.

What resources do I have to be successful? All the materials you need are on this OneNote. In order to participate in the final discussion, you will need to go onto schoology. Your teachers are still available to you and will communicate in means that work for them and you.

Use the timeline below to keep track and learn as much as you can within the time you have away from the school building. Week 1: Finish 4.1, 4.2, and 4.3a-c, SIR PART 1 - be sure you understand the band of stability, fill in the learning tracking tool Week 2: Finish 4.4, 4.5, and 4.6, SIR PART 2- be sure you can draw simple models of fission and fusion, fill in learning tracking tool Week 3: Finish 4.7a-c – be sure you can draw simple models of alpha and beta decay, fill in learning tracking tool Week 4: Finish 4.8a-b, SIR PART 3, and 4.9 - be sure you can explain half-life and what happens to unstable atoms, finish learning tracking tool Week 5: Finalize understanding of Nuclear Sciences, fill in discussion assignment on schoology (4.9), contact teacher for any assessments

Chem A Unit Page 1 4.1 Nuclear Phenomenon Tuesday, March 17, 2020 11:20 AM

Driving Question: Does the pursuit of Nuclear Science benefit or harm society?

Intro: For the Nuclear Unit, we will be developing a pro/con argument for the study of nuclear science. By the end of the unit, you shall be able to argue FOR and AGAINST the pursuit of nuclear science.

Directions: Answer the two questions below BEFORE continuing in the activity. Then watch videos showing the costs of nuclear science. You will then answer questions about the costs. After that, you will do independent research about the benefits.

BEFORE watching the videos or hearing the story, answer these two questions: 1. What are some costs of nuclear science? 2. What are some benefits of nuclear science?

WARNING: You are going to watch a video about the devastation from the Atomic Bombs dropped on Hiroshima and Nagasaki. These are real events where numerous people died.

CBBC Newsround: Hiroshima - A survivor's story in animation

Now watch these videos to continue thinking about the costs of Nuclear Science:

The Atomic Bombing of Hiroshima | The Daily 360 | The New York Times

Chem A Unit Page 2 Hanford nuclear site is America's most toxic place

COSTS: Reflect on what you've seen so far. 3. What are some costs to nuclear research and technology?

4. Discuss the costs with a family member or friend. What did they say?

BENEFITS: Go to this website and look around: https://www.nei.org/advantages

Pick TWO advantages to read about and take notes. 5. Take notes from the site: Topic 1 Picked: Notes (must take at least 3 notes on the benefits):

Chem A Unit Page 3 Topic 2 Picked: Notes (must take at least 3 notes on the benefits):

6. Discuss your advantage with a family member or a friend. Summarize what they said:

7. Add to your Learning Tracking Tool what you discovered in this first activity. Be sure to had a BENEFIT and a COST.

Chem A Unit Page 4 4.2 Isotopes Tuesday, March 17, 2020 11:23 AM

Pre Activity questions: 1. What is an isotope?

Atom Protons Electrons Neutrons A 3 3 4 B 3 2 3

2. Examine the table above - are the atoms A and B of the same element? Explain how you know.

Lab Objective: Why is there a decimal for the mass of elements on the periodic table?

Below is a data set for a same of hydrogen atoms. A 1 gram sample of hydrogen was evaluated for all the different types of isotopes within the sample:

Isotopes Found Hydrogen-1 Hydrogen-2 Hydrogen-3 Atomic Mass 1 AMU 2 AMU 3 AMU Total mass within 1g sample 0.99g 0.099g 0.001g Percent of total mass 99% 0.99% 0.01%

3. The atomic mass recorded on the periodic table for Hydrogen is 1.01 AMU. Notice that each isotope of Hydrogen is ALWAYS a whole number. Where do you think the decimal came from looking at the data above?

The mass on the periodic table is called a WEIGHTED AVERAGE. This means that the mass is not of a single atom, but it is the average of all possible isotopes found of that atom. To calculate weighted average, you take the mass of each isotope, multiply it by the percent of the sample it makes up, and then add them together. Divide this number by 100 and you get the AVERAGE ATOMIC MASS.

(99 X 1) + (.99 X 2) + (.01 X 3) = 101 ÷ 100 = 1.01 AMU

4. Using the above paragraph, explain why the mass on the periodic table is a decimal.

5. For hydrogen, which isotope is closest to the mass recorded on the periodic table? Why do you think this is based on the data for hydrogen?

Below is the data set for a sample of Carbon

Isotopes Found Carbon-12 Carbon-13 Carbon-14 Other Isotopes Atomic Mass 12 AMU 13 AMU 14 AMU Various Total Mass within 1g sample 0.99g 0.009 0.0009 0.0001g Percent of total mass 99% 0.9% 0.09% 0.01%

6. Based on the data above, which of these would most likely be the recorded mass of Carbon on the periodic table? a. 12 b. 12.01 c. 13

Chem A Unit Page 5 c. 13 d. 13.01 e. 14 f. 14.01

7. Explain your answer to 6:

8. If you had 1000 carbon atoms and pulled out just one atom, what would its mass most likely be?

9. Explain your answer to 8:

10. Based on the average atomic mass on the periodic table, examine the 3 isotopes of Sulfur. a. Fill in the table below comparing the 3 isotopes.

Protons Electrons Neutrons Mass

b. If were able to separate out a single sulfur atom from a 1g sample, how many neutrons would you expect it to have? Explain your answer using the mass on the periodic table.

The chart below shows the isotopes that exist for the first six elements. Use the chart and a periodic table to answer questions 11 and 12.

Chem A Unit Page 6 11. How many isotopes does hydrogen have? How are they different from each other?

12. Fill in the bolded boxes with the isotope symbol for the isotopes of lithium, beryllium, and boron. You may have to use the drawing tool. Or you could create a text box and drag it over.

Use the Isotopes of Elements Chart (4.3b) to answer questions 13-15 13. Give the isotope name and symbol of the only naturally occurring isotope of phosphorus.

14. Which element has the most isotopes? How many isotopes does this element have?

15. Find Tin (50) a. Fill in the top box with the isotope symbol and isotope name for 3 possible isotopes.

Chem A Unit Page 7 a. Fill in the top box with the isotope symbol and isotope name for 3 possible isotopes. b. Determine number of protons, electrons, neutrons and mass for each isotope. c. Circle the isotope that you would mostly like have if you managed to isolate a single atom of tin.

Protons Electrons Neutrons Mass

Additional Practice Use the phet below and play around with the Mixtures tab. You should be able to answer these two questions when you finish: 16. Explain why the periodic table has a decimal:

17. Determine the most common isotope of elements based on the number on the period table:

Isotopes and Atomic Mass

Chem A Unit Page 8 Chem A Unit Page 9 4.3a Band of Stability Tuesday, March 17, 2020 11:25 AM

Objective: Determine if an atom is stable, unstable (aka radioactive), or does not exist based on the Isotopes graph. Background Info: Isotopes of elements found in nature are all located within the band of stability on the graph (4.3b). Those elements found in the middle of the band have a very stable nucleus, while those elements on the outer edges of the band have an unstable nucleus and are said to be radioactive. However, some combination of protons and neutrons in the nucleus are so unstable that they cannot even exist long enough to be recognized as elements and these fall outside the band of stability. Instructions: a) determine the number of subatomic particles for each element at the top of the next page. b) locate where the atoms would be on the graph. c) label each atom after it has been plotted (see Potassium-41 as an example)

Questions to Answer NOTE: You will need to use the 4.3 Isotopes of Elements graph to complete this assignment

1. For the elements below, identify how many protons, neutrons, and electrons. Then identify if would be common, radioactive, or non-existent in nature (so radioactive it decays instantly)

# p: # p: # p: # p: # p: # p: # e: # e: # e: # e: # e: # e: # n: # n: # n: # n: # n: # n: Common Common Common Common Common Common Radioactive Radioactive Radioactive Radioactive Radioactive Radioactive Non-Existent Non-Existent Non-Existent Non-Existent Non-Existent Non-Existent

2. Were there any atoms not already plotted on the graph? What does it mean if they are not on the graph?

3. How can there be two different atoms of iridium? How are they different?

4. Would a small atom (less than 40 protons) be found in nature if it has the same number of protons and neutrons (1:1 ratio)? Explain. (see the video below if you need extra information)

5. Would a large atom (more than 40 protons) be found in nature if it has the same number of protons & neutrons (1:1 ratio)? Explain.

6. Imagine a chemist was trying to create an atom with 60 protons and a mass number of 155. Would this be possible? Why or why not? (Show where it would fall on the graph.)

7. If an element had 90 protons, how many neutrons would be a good number for it to have in order to be considered a stable element? What element would this be? (Show where It would fall on the graph.)

Stable & Unstable Nuclei | Radioactivity | Physics | FuseSchool

Chem A Unit Page 10 Chem A Unit Page 11 4.3b Isotopes of Elements Chart (Band of Stability) Tuesday, March 17, 2020 11:30 AM

Reading the Isotopes Graph: 1. Start by finding the atomic number of the element on the X axis. 2. From that atomic number, go up until you see the boxes that are lined up with that number 3. Look at where they line up with the number of neutrons (notice it is NOT the mass – you have to calculate that yourself) to figure out which isotopes exist 4. Thinking about the colors: a. If the box is BLACK, it is the most common b. If the box is GRAY, it is common but not the most c. If the box is WHITE, it is radioactive and will naturally decay d. If there is no box, it is not an element that exists in nature. This means that it would be so radioactive that it would immediately decay.

e.

Chem A Unit Page 12 Chem A Unit Page 13 4.3c Radioactive Element Articles Wednesday, March 18, 2020 1:31 PM Reading 1: Benefit of Radioactive elements Radioisotopes This therapy uses radioactive liquids known as radioisotopes or radionuclides to destroy cancer cells. The liquid can be given: • by mouth as a drink or capsules • as an injection into a vein. Cancer cells take in the radioisotope more than normal cells do. This means they get a higher dose of radioactivity. This eventually destroys the cancer cells. Your team will tell you how you will have your treatment and any possible side effects. Radiation safety during radioisotope therapy Your treatment is planned to give you the amount of radiation needed to treat the cancer safely and effectively. But your team are careful to protect other people around you from radiation. Safety measures may be slightly different in different hospitals. Your team will explain what to expect. After treatment, your body fluids are slightly radioactive for a time. Your team will give you instructions about using the toilet and cleaning up any spilled body fluids safely. You may be advised to avoid close contact with children or pregnant women for a time. If your treatment involves a stay in hospital, you may be cared for in a single treatment room. You may be asked to stay in your room at all times. Tell your team if you are worried about this so they can help. Your team will tell you any other safety measures you need to follow. Iodine-131 This is the most common type of radioisotope therapy. It is mainly used to treat some types of thyroid cancer. It may also be used to treat other rarer neuroendocrine tumours. You usually have it as capsules or a drink. But it can also be given as an injection into a vein in the arm. You may have to stay in hospital to have this treatment. We have more information about treating thyroid cancer and neuroendocrine tumours. Strontium-89 and Samarium-153 These radioisotopes can be used to treat some types of cancer that have spread to the bones (metastatic bone cancer). This treatment can help reduce bone pain and improve quality of life. You can usually go home soon after having this treatment. We have more information about treating metastatic bone cancer. Radium-223 This radioisotope is sometimes used to treat prostate cancer that has spread to the bones. It may be used if hormone therapy alone is no longer controlling the cancer. You can usually go home soon after having this treatment. We have more information about treating metastatic bone cancer and about advanced prostate cancer. Found at: www.macmillan.org.uk/information-and-support/treating/radiotherapy

Radioactive iodine (radioiodine) therapy The thyroid absorbs almost all iodine that enters a body. Therefore, a type of radiation therapy called

Chem A Unit Page 14 The thyroid absorbs almost all iodine that enters a body. Therefore, a type of radiation therapy called radioactive iodine (also called I-131 or RAI) can find and destroy thyroid cells not removed by surgery and those that have spread beyond the thyroid. Doctors who prescribe radioactive iodine therapy are usually endocrinologists or nuclear medicine specialists. Radioactive iodine treatment is an option for some people with papillary and follicular thyroid cancer. Radioactive iodine is used to treat people with differentiated thyroid cancers that have spread to lymph nodes or to distant sites. A small test dose may be given before full treatment to be sure that the tumor cells will absorb the I-131. Patients with MTC or anaplastic thyroid cancer should not be treated with I-131. I-131 therapy is given in either liquid or pill form. Patients who receive I-131 to destroy cancer cells may be hospitalized for 2 to 3 days, depending on several factors, including the dose given. Patients are encouraged to drink fluids to help the I-131 pass quickly through the body. Within a few days, most of the radiation is gone. Talk with your doctor about ways to limit radiation exposure to other people, including children, who may be around you during this treatment and the days following it. In preparation for I-131 therapy after surgery, patients are usually asked to follow a low-iodine diet for 2 to 3 weeks beforehand. In addition to the low-iodine diet, patients will be asked to either stop taking thyroid hormone replacement pills temporarily or to receive injections of recombinant TSH (Thyrogen) while taking the hormone replacement. If the hormone therapy is stopped during the preparation period, the patient will likely experience the side effects of hypothyroidism (see above). It is important to discuss the possible short-term and long-term effects of I-131 therapy with your doctor. On the first day of treatment, patients may experience nausea and vomiting. In certain circumstances, pain and swelling can occur in the areas where the radioactive iodine is collected. Because iodine is concentrated in salivary gland tissue, patients may experience swelling of the salivary glands. This may result in xerostomia, sometimes called dry mouth. Large or cumulative doses of radioactive iodine may cause infertility, which is the inability to produce a child, especially in men. It is recommended that women avoid pregnancy for at least 1 year after I-131 treatment. There is a risk of secondary cancer with the use of I-131 (see Follow-up Care). Occasionally, patients may require repeated treatments over time. However, there is a maximum total dose of radioactive iodine allowed over time, and once reached, this may prevent further use of this treatment.

Found at: www.cancer.net

Reading 2: Costs of Radioactive Elements and Exposure Introduction During the Cold War in the mid-1940s through early 1960s, the U.S. government conducted about 100 nuclear weapons (atomic bomb) tests in the atmosphere at a test site in Nevada, more than 100 in the Pacific, and one—the first ever—in New Mexico. The radioactive substances released by these tests are known as "fallout." They were carried thousands of miles away from the test site by winds. As a result, people living in the United States at the time of the testing were exposed to varying levels of radiation. Among the numerous radioactive substances released in fallout, there has been a great deal of concern about and study of one radioactive form of iodine--called iodine-131, or I-131. I-131 collects in the thyroid gland. People exposed to I-131, especially during childhood, may have an increased risk of thyroid disease, including thyroid cancer. Thyroid cancer is uncommon and is usually curable. Typically, it is a slow-growing cancer that is highly treatable. About 98 out of 100 people who are diagnosed with thyroid cancer survive the disease for at least five years after diagnosis. The thyroid controls many body processes, including heart rate, blood pressure, and body temperature, as well

Chem A Unit Page 15 The thyroid controls many body processes, including heart rate, blood pressure, and body temperature, as well as childhood growth and development. It is located in the front of the neck, just above the top of the breastbone and overlying the windpipe. Although the potential of developing thyroid cancer from exposure to I-131 from nuclear weapons testing is small, it is important for Americans who grew up during the atomic bomb testing between 1945 and 1963 to be aware of risks. How Americans Were Exposed to I-131 Because of wind and rainfall patterns, the distribution of I-131 fallout varied widely after each test. Therefore, although all areas of the United States received fallout from at least one nuclear weapons test, certain areas of North America received more fallout than others. Scientists estimate that the larger amounts of I-131 from the Nevada test site fell over some parts of Utah, Colorado, Idaho, Nevada, and Montana. But I-131 traveled to all states, particularly those in the Midwestern, Eastern, and Northeastern United States. Some of the I-131 collected on pastures and on grasses. Depending on the location, grazing cows and goats sometimes consumed contaminated grasses resulting in I-131 collecting in the animals' milk. Much of the health risk associated with I-131 occurred among milk-drinkers-- usually children. From what is known about thyroid cancer and radiation, scientists think that people who were children during the period of atomic bomb testing are at higher risk for developing thyroid cancer. In addition to nuclear testing in Nevada, the Pacific, and New Mexico, Americans were potentially exposed to I-131 from a number of events, including: • Nuclear testing by other nations elsewhere in the world (mainly in the 1950s and 1960s) • Nuclear power plant accidents (such as the Chernobyl accident in 1986 and the Fukushima accident in 2011 (primarily Americans in Japan) • Releases from atomic weapons production plants (such as the Hanford facility in Washington state from 1944 to 1957) Scientists are working to find out more about ways to measure and address potential I-131 exposure. They are also working to find out more about other radioactive substances released by fallout and their possible effects on human health. The Search for Answers Congress directed government health agencies to investigate the I-131 problem many years ago, and to make recommendations to Americans who might have related health risks. Gathering information turned out to be very complicated. Record-keeping was incomplete at the time of the bomb testing. Much of the information needed to calculate an individual's dose of I-131 and associated risk is either unreliable or unavailable. Despite such challenges, government agencies organized expert scientific teams that have devoted many years to learning more about I-131. A number of reports have been published documenting what they have learned (1997, 1999). This information was put together to educate the American people about the potential health risks from exposure to I-131 from nuclear weapons testing. I-131's Rapid Breakdown The "active" in "radioactive" means that unstable substances produced in nuclear reactions break down and change, so that they eventually become stable and no longer release radiation. The rate of breakdown can occur quickly in some radioactive substances, often within a few days. Half of the I-131 released during each atomic bomb test was gone in about 8 days. Almost all of it was gone (less than 1 percent remained) 80 days after the test. Like all radioactive substances, I-131 releases radiation as it breaks down. It is this radiation that can injure human tissues. But I-131's steady breakdown means that the amount of I-131 present in the environment after a bomb test steadily decreased. Therefore, farm animals that grazed in fields within a few days after a test

Chem A Unit Page 16 a bomb test steadily decreased. Therefore, farm animals that grazed in fields within a few days after a test would have consumed higher levels of I-131 than animals grazing later. The Milk Connection People younger than 15 at the time of aboveground testing (between 1945 and 1963) who drank milk, and who lived in the Mountain West, Midwestern, Eastern, and Northeastern United States, probably have a higher thyroid cancer risk from exposure to I-131 in fallout than people who lived in other parts of the United States, who were over the age of 15 in the 1940s, or who did not drink milk. Their thyroid glands were still developing during the testing period. And they were more likely to have consumed milk contaminated with I-131. The amount of I-131 people absorbed depends on: • Their age during the testing period (between 1945 and 1963) • The amount and source of milk they drank in those years • Where they lived during the testing period Age and residence during those years are usually known. But few people can recall the exact amounts or sources of the milk they drank as children. While the amount of milk consumed is important in determining exposure to I-131, it is also important to know the source of the milk. Fresh milk from backyard or farm cows and goats usually contained more I-131 than store-bought milk. This is because processing and shipping milk allowed more time for the I-131 to break down. About Thyroid Disease There are two main types of thyroid diseases: Noncancerous Thyroid Disease Some thyroid diseases are caused by changes in the amount of thyroid hormones that enter the body from the thyroid gland. Doctors can screen for these with a simple blood test. Noncancerous thyroid disease also includes lumps, or nodules, in the thyroid gland that are benign and not cancerous. Thyroid Cancer Thyroid cancer occurs when a lump, or nodule, in the thyroid gland is cancerous. Thyroid Cancer and I-131 Thyroid cancer accounts for a little less than 4 percent of all cancers diagnosed in the United States. Incidence has been going up in recent years, in part due to increased detection. Researchers suspect that rising rates of obesity are also influencing rates. However, these two factors do not fully explain the increases. Typically, thyroid cancer is slow-growing, highly treatable, and usually curable. About 98 out of 100 people who are diagnosed with thyroid cancer survive the disease for at least five years, and about 92 out of 100 people survive the disease for at least 20 years after diagnosis. The cause of most cases of thyroid cancer is not known. Exposure to I-131 can increase the risk of thyroid cancer. It is thought that risk is higher for people who have had multiple exposures and for people exposed at a younger age. But even among people who have documented exposures to I-131, few develop this cancer. It is known that children have a higher-than-average risk of developing thyroid cancer many years later if they were exposed to radiation. This knowledge comes from studies of people exposed to x-ray treatments for childhood cancer or noncancerous head and neck conditions, or as a result of direct radiation from the atomic bombings of Hiroshima and Nagasaki. The thyroid gland in adults, however, appears to be more resistant to the effects of radiation. There appears to be little risk of developing thyroid cancer from exposure to I-131 or other radiation sources as an adult. For more on thyroid cancer, see NCI’s Thyroid Cancer page. Who's at Risk?

Chem A Unit Page 17 Who's at Risk? How can people reach a sound decision about their risk of thyroid cancer? When is it time to visit a doctor? A "personal risk profile" includes four key points that may influence a person's decision to visit a doctor or other health professional for evaluation: • Age—People who are now 50 years of age or older, particularly those born between 1936 and 1963 and who were children at the time of testing, are at higher risk. • Milk drinking—Childhood milk drinkers, particularly those who drank large quantities of milk or those who drank unprocessed milk from farm or backyard cows and goats, have increased risk. • Childhood residence—The Mountain West, Midwest, East, and Northeast areas of the United States generally were more affected by I-131 fallout from nuclear testing. • Medical signs—A lump or nodule that an individual can see or feel in the area of the thyroid gland requires attention. If you can see or feel a lump or nodule, it is important that you see a doctor. Key Facts Scientists know that: • I-131 breaks down rapidly in the atmosphere and environment • Exposure was highest in the first few days after each nuclear test explosion • Most exposure occurred through drinking fresh milk • People received little exposure from eating fruits and leafy vegetables as compared to drinking fresh milk because although I-131 was deposited on fruits and leafy vegetables, the I-131 in fallout was deposited only on the surface; people generally wash or peel fruits and leafy vegetables • Thyroid cancer is uncommon, usually curable, and approximately 2 to 3 times more common in women Reliable information about I-131's impact on human health has been difficult to collect, but scientists think that: • Risk for thyroid cancer increases with exposure, but even among people exposed to I-131, few develop this cancer • People exposed as children have a higher risk than people exposed as adults Taking Care of Yourself Key steps to estimating personal risk of thyroid cancer, and taking charge of personal thyroid health include: • Using the "personal risk profile" described above (see Who's at Risk?) • Using the thyroid dose and risk calculator to estimate radiation dose and risk of developing thyroid cancer from fallout exposure from nuclear tests • Taking this material to a health care professional to discuss dose estimates and steps—if any—required for further evaluation • Getting more information by calling NCI's Cancer Information Service at 1-800-4-CANCER

Chem A Unit Page 18 SIR PART 1: Nucleus of the Atom Monday, March 23, 2020 11:26 AM

Chem A Unit Page 19 Answer the questions below:

1. Calculate the atomic mass of boron if it has the following distribution in a sample of 100 atoms: (20 atoms are boron-10, 80 atoms are boron-11). Show your work.

2. The atomic mass of chlorine is 35.45 amu. Why is this number not a whole number?

Chem A Unit Page 20 3. Describe 2 different ways that the nucleus of an atom could change?

4. Scientists who study the creation of new elements must take a lot of safety precautions. Why is that?

Chem A Unit Page 21 4.4a Fission Phet Tuesday, March 17, 2020 11:30 AM

Learning Goals: A. Explain the concept of a “chain reaction” in terms of subatomic particles and energy B. Connect the concept of nuclear fission of uranium with a chain reaction. C. Explain how a nuclear reactor works and how a fission reaction is monitored

Phet: https://phet.colorado.edu/en/simulation/nuclear-fission This is a Java phet, so it will need to be downloaded and opened.

If you cannot open the simulation, you may do these things: 1. Watch this video: https://kcts9.pbslearningmedia.org/resource/nvhe.sci.chemistry.fission/a-fission-chain-reaction/

2. Use this visualization. If it stops and says "Subscription" just refresh the page and try again. https://www.edumedia-sciences.com/en/media/491-fission

3. There is a video at the bottom of the page of the simulation. Watch that as well.

4. Answer all questions using those resources

Part 1: “Fission: One Nucleus”

Instructions: i. You will begin on the “one nucleus screen.” ii. You will see a “gun” that will fire a particle at the nucleus. iii. To fire the gun, click on the red circle. iv. To the right of the simulation area you will see the legend of the symbols for the simulation. v. In the chart at the bottom you will see the blue line that represents the potential energy of the nucleus. vi. The gold line represents the total energy of the nucleus/system.

Questions: 1. Write the uranium nucleus being used in the Atomic Symbol Format.

1. Fire the particle gun at the nucleus, draw a picture with captions that describes what happens to the nucleus. You may use the draw tool here or draw on a separate piece of paper and describe with words what you drew. NOTE: Watch carefully, because you want to describe the process from the time that the particle strikes the nucleus until the nucleus changes.

3. When the nucleus changes, describe everything that comes out.

4. Create a nuclear decay equation for this process. The first part of that equation is written below. The two daughter nuclei formed are Krypton-92 and Barium-141. Note: your equation should show a middle part and an ending, so a second arrow to the equation

5. Now, pay attention to the chart at the bottom of the simulation. Answer these questions to analyze the graph: a. What happens to the amount of energy in the atom the moment the neutron is added? b. Do all the pieces have more or less energy than the Uranium-236? c. Why do you think this happens?

6. Describe what you would do to make U-235 unstable.

Chem A Unit Page 22 Be sure you understand a single atom going through fission before moving on!

Part 2: “Chain Reaction”

Instructions: i. Select the “Chain Reaction” tab at the top. ii. Experiment with settings- change them, shoot the neutron gun and watch what happens. iii. Set the initial number of U-235 nuclei to 100

Questions: 7. What happens when you fire the neutron gun? Note: the gun can rotate; grab it to drag it around.

8. Explain why this is called a “chain reaction”.

Set the initial number of U-238 nuclei to 100.

9. Explain what happens when you fire the gun and if this is a chain reaction or not.

Set the initial numbers of U-235 nuclei and U-238 nuclei to the numbers in the following table. 10. Record your results of each combination below. Table of Experimentation with Chain Reactions of different Uranium Isotopes U-235 100 70 50 30 0 U-238 0 30 50 70 100 % of 235U fissioned after 1 firing # firings required to fission all 235U N/A

11. What happens to the reaction as the proportion of U-238 nuclei increases?

12. If you were trying to design the most efficient fission reactor possible, what ratio of U-235 to U-238 would you want? Explain why.

Click on the containment vessel box as shown to the right and experiment with adjusting the number of U-235 and U-238 atoms in the vessel. Also experiment with adjusting the size of the containment vessel.

13. What factor(s) affect whether or not the containment vessel explodes / creates a bomb. Explain.

Be sure you understand Chaing Reaction before moving onto the Nuclear Reactor

Part 3: “Nuclear Reactor” Instructions: i. Select the “Nuclear Reactor” tab at the top. ii. Experiment with changing the settings and firing the neutrons and watch what happens.

Note: As the reactor get darker orange in color this indicates that it is approaching meltdown. A meltdown can destroy the reactor and release dangerous nuclear material into the environment.

14. The bar graphs on the right of the display show the “Power Output” and the “Energy Produced”. What is the difference between these two quantities? In your answer, discuss how these two graphs have an influence on the temperature inside of the reactor as shown by the little thermometer next to the reactor.

Chem A Unit Page 23 15. Watch the fission reactions closely as they happen. Specifically watch what happens to the loose neutrons after the reaction? a. What happens if the neutrons hit another nucleus? b. What happens if the neutrons hit a control rod? c. What might the control rods contain? Explain.

16. Compare the chain reaction that occurs when the control rods are inserted further into the reactor versus when they are pulled all/mostly out of the reactor.

17. If the purpose of a nuclear reactor in a power plant is to produce energy, why are there control rods? Answer this question using the words: energy, power and temperature.

18. Name 2-3 things about the control rods that you would like to know more about in order to understand how they work in a reactor. Why would knowing these things help you to explain how the rods work?

19. Describe the similarities and differences between a nuclear reactor and a nuclear bomb.

Watch This Video to answer question 20: PWR Nuclear Power Plant Animation

20. After watching, describe in a short paragraph how heat released from a nuclear reactor turns into electric energy that we can use to live our everyday lives.

Part 4: Fission Guided Notes

1. Nuclear Fission is the (splitting/combining) of a(n) (stable/unstable) atom into two or more smaller nuclei. 2. An unstable atom is referred to as (radioactive/an isotope) because it will go through decay or fission. 3. For the fission of Uranium, the atom starts as mostly (stable/unstable) but then the atom is hit with a (proton/neutron/electron). 4. During the nuclear reaction, the added particle causes the big atom to now be more (stable/unstable). 5. At the end, there are two smaller, more (stable/unstable) atoms. 6. Nuclear fission releases a (small/large/massive) amount of energy in the form of heat, light, and sound.

Chem A Unit Page 24 7. The left side of the equation above is called the (reactants/products) and the right is called the (reactants/products). 8. The mass in the reactants is (equal to/greater than/less than) the mass in the products. Hint: be sure to add them all up 9. The proton amount in the reactants is: ______, in the products it is: ______. 10. The mass amount in the reactants is: ______, in the products it is: ______. 11. Fission Nuclear Reactors release a massive amount of energy because they cause a ______between many atoms of Uranium.

Fission Screencast

Chem A Unit Page 25 4.4b Fission Power Plants vs Coal Tuesday, March 17, 2020 11:30 AM

Part 1: Reading Read this interview about Coal and Power Plants: https://www.researchgate.net/publication/281715047_One_gram_of_uranium_is_equivalent_to_15-2_tons_of_coal

Complete the table below as you read:

Nuclear Power Coal Amount of electrical power made per mass of substance Nuclear waste versus mercury contamination Amount of nuclear waste vs amount of waste for coal Emissions of Nuclear Waste vs Emissions of coal

You may continue to read more articles. If you do, add your notes here:

Part 2: Watching Watch the 3 short videos at the bottom of the page and add to the table below as you watch.

Is Nuclear Power beneficial?

Yes - Reasoning No - Reasoning

General Information:

Video 1: General Info Video – Add at least SEVEN notes to your general information below the table above. Nuclear Energy Explained: How does it work? 1/3

Video 2: Why Nuclear is NOT beneficial – must write the 3 main points and have at least TWO details for each point. 3 Reasons Why Nuclear Energy Is Terrible! 2/3

Chem A Unit Page 26 Video 3: Why Nuclear IS beneficial – must write the 3 main points and have at least TWO details for each point. 3 Reasons Why Nuclear Energy Is Awesome! 3/3

Chem A Unit Page 27 4.5a Fusion Activity Tuesday, March 17, 2020 11:30 AM Part 1: Fusion in Stars The Most Astounding Fact - Animated

First read this article: https://www.popsci.com/neutron-star-gold/#page-2 Then watch this video: https://www.nytimes.com/2017/10/16/science/ligo-neutron-stars-collision.html?smid=pl-share 1. What did you learn from the videos and article? 2. Where do most our heavy elements come from? 3. Would this suggest fusion releases/needs a lot of energy or a little bit of energy? Explain 4. Would these resources suggest that fusion is natural or unnatural?

PART 2: Modeling Nuclear Fusion in Stars MATERIALS 1. 15 White Marshmallows (or one type of candy) 2. 15 Gummy Bears (or another type of candy)

INSTRUCTION FOR CANDY FUSION 1. The materials represent the following: • 1 Gummy Bear = 1 Proton • 1 White Marshmallow = 1 Neutron 2. Use the candies to create the models of: 1H, 2H and 3H shown below, then eat them. Fill in the numbers below each image. 1H 2H 3H

Chem A Unit Page 28 Number of Protons in Hydrogen-1: Number of Protons in Hydrogen-2: Number of Protons in Hydrogen-3: Number of Neutrons in Hydrogen-1: Number of Neutrons in Hydrogen-2: Number of Neutrons in Hydrogen-3:

3. Create models three identical atoms of Helium-4. Sketch your models, but keep them for the next steps.

4. Smoosh all the He atoms together to make one new element. a. What element did you make (count the gummy bears and use the periodic table)?

b. Label it with the appropriate symbol (use isotopic notation format)

c. Draw the element

d. How many protons (in total) were present before the reactions (add all Helium together)? How many were present after the reaction?

e. How many neutrons (in total) were present before the reactions? How many were present after the reaction?

5. What element would you make if you fused another 4He with the carbon atom you created in Step 4? a. Model the reaction (in other words, make it with the candies) b. Draw the product

c. Label it with the appropriate symbol.

6. What element would you make if you fused another 4He with the oxygen atom you created in Step 5? a. Model it with the candies b. Complete the nuclear equation for the reaction below.

______+ ______à ______

7. How could you form magnesium from the element you created in Question 6? a. Model it b. Write a nuclear equation for the reaction below (remember to use an arrow)

PART 3: Analysis Chem A Unit Page 29 PART 3: Analysis 8. Does nuclear fusion affect the total of the mass numbers before and after the reaction? Cite specific evidence to support your answer.

9. Does nuclear fusion affect the total of the atomic numbers before and after the reaction? Cite specific evidence to support your answer.

10. In normal function of stars, iron is the heaviest element formed. What is a fusion reaction that could produce 52Fe?

11. Is energy absorbed or produced by nuclear fusion? (Hint: think about where fusion occurs)

12. What are some limitations of using candies as a model for fusion?

Chem A Unit Page 30 4.5b Fusion Readings Tuesday, March 17, 2020 11:30 AM Reading 1 (COST – Weaponry) Hydrogen Bomb vs. Atomic Bomb: What's the Difference? By Stephanie Pappas, Live Science Contributor | September 22, 2017 04:53pm ET

North Korea is threatening to test a hydrogen bomb over the Pacific Ocean in response to President Donald Trump ordering new sanctions on individuals, companies and banks that conduct business with the notoriously reclusive country, according to news reports.

"I think that it could be an H-bomb test at an unprecedented level, perhaps over the Pacific," North Korea's Foreign Minister Ri Yong Ho told reporters this week during a gathering of the United Nations General Assembly in New York City, according to CBS News. Ri added that, "it is up to our leader."

Hydrogen bombs, or thermonuclear bombs, are more powerful than atomic or "fission" bombs. The difference between thermonuclear bombs and fission bombs begins at the atomic level.

Fission bombs, like those used to devastate the Japanese cities of Nagasaki and Hiroshima during World War II, work by splitting the nucleus of an atom. When the neutrons, or neutral particles, of the atom's nucleus split, some hit the nuclei of nearby atoms, splitting them, too. The result is a very explosive chain reaction. The bombs dropped on Hiroshima and Nagasaki exploded with the yield of 15 kilotons and 20 kilotons of TNT, respectively, according to the Union of Concerned Scientists. In contrast, the first test of a thermonuclear weapon, or hydrogen bomb, in the United States in November 1952 yielded an explosion on the order of 10,000 kilotons of TNT. Thermonuclear bombs start with the same fission reaction that powers atomic bombs — but the majority of the uranium or plutonium in atomic bombs actually goes unused. In a thermonuclear bomb, an additional step means that more of the bomb's explosive power becomes available. First, an igniting explosion compresses a sphere of plutonium-239, the material that will then undergo fission. Inside this pit of plutonium-239 is a chamber of hydrogen gas. The high temperatures and pressures created by the plutonium-239 fission cause the hydrogen atoms to fuse. This fusion process releases neutrons, which feed back into the plutonium-239, splitting more atoms and boosting the fission chain reaction. Governments around the world use global monitoring systems to detect nuclear tests as part of the effort to enforce the 1996 Comprehensive Test Ban Treaty (CTBT). There are 183 signatories to this treaty, but it is not in force because key nations, including the United States, did not ratify it. Since 1996, Pakistan, India and North Korea have carried out nuclear tests. Nevertheless, the treaty put in place a system of seismic monitoring that can differentiate a nuclear explosion from an earthquake. The CTBT International Monitoring System also includes stations that detect the infrasound — sound whose frequency is too low for human ears to detect — from explosions. Eighty radionuclide monitoring stations around the globe measure atmospheric fallout, which can prove that an explosion detected by other monitoring systems was, in fact, nuclear.

Reading 2 (BENEFIT – Energy) We Are Closer Than Ever to Unlimited Clean Energy Even a small fusion reactor could power more than 150,000 homes.

For centuries, humans have dreamed of harnessing the power of the sun to energize our lives here on Earth. But we want to go beyond collecting solar energy, and one day generate our own from a mini-sun. If we’re able to solve an extremely complex set of scientific and engineering problems,

Chem A Unit Page 31 mini-sun. If we’re able to solve an extremely complex set of scientific and engineering problems, fusion energy promises a green, safe, unlimited source of energy. From just one kilogram of deuterium extracted from water per day could come enough electricity to power hundreds of thousands of homes. Since the 1950s, scientific and engineering research has generated enormous progress toward forcing hydrogen atoms to fuse together in a self-sustaining reaction – as well as a small but demonstrable amount of fusion energy. Skeptics and proponents alike note the two most important remaining challenges: maintaining the reactions over long periods of time and devising a material structure to harness the fusion power for electricity. As fusion researchers at the Princeton Plasma Physics Lab, we know that realistically, the first commercial fusion power plant is still at least 25 years away. But the potential for its outsize benefits to arrive in the second half of this century means we must keep working. Major demonstrations of fusion’s feasibility can be accomplished earlier – and must, so that fusion power can be incorporated into planning for our energy future. Unlike other forms of electrical generation, such as solar, natural gas, and nuclear fission, fusion cannot be developed in miniature and then be simply scaled up. The experimental steps are large and take time to build. But the problem of abundant, clean energy will be a major calling for humankind for the next century and beyond. It would be foolhardy not to exploit fully this most promising of energy sources. Why Fusion Power? In fusion, two nuclei of the hydrogen atom (deuterium and tritium isotopes) fuse together. This is relatively difficult to do: Both nuclei are positively charged, andtherefore repel each other. Only if they are moving extremely fast when they collide will they smash together, fuse and thereby release the energy we’re after. This happens naturally in the sun. Here on Earth, we use powerful magnets to contain an extremely hot gas of electrically charged deuterium and tritium nuclei and electrons. This hot, charged gas is called a plasma. The plasma is so hot – more than 100 million degrees Celsius – that the positively charged nuclei move fast enough to overcome their electrical repulsion and fuse. When the nuclei fuse, they form two energetic particles – an alpha particle (the nucleus of the helium atom) and a neutron. Heating the plasma to such a high temperature takes a large amount of energy – which must be put into the reactor before fusion can begin. But once it gets going, fusion has the potential to generate enough energy to maintain its own heat, allowing us to draw off excess heat to turn into usable electricity. Fuel for fusion power is abundant in nature. Deuterium is plentiful in water, and the reactor itself can make tritium from lithium. And it is available to all nations, mostly independent of local natural resources. Fusion power is clean. It emits no greenhouse gases, and produces only helium and a neutron. It is safe. There is no possibility for a runaway reaction, like a nuclear-fission “meltdown.” Rather, if there is any malfunction, the plasma cools, and the fusion reactions cease. All these attributes have motivated research for decades, and have become even more attractive

Chem A Unit Page 32 All these attributes have motivated research for decades, and have become even more attractive over time. But the positives are matched by the significant scientific challenge of fusion. From: https://futurism.com/fusion-energy-provides-a-clean-unlimited-source-of-power

Chem A Unit Page 33 SIR PART 2: Fission/Fusion and Stability Monday, March 23, 2020 11:26 AM

Chem A Unit Page 34 Chem A Unit Page 35 Chem A Unit Page 36 Chem A Unit Page 37 Analysis and reading questions:

1. Describe the difference between fission and fusion.

2. Why are the neutrons released during fission important to a fission chain reaction?

3. A common statement from science is, “We are all stardust.” Use your understanding of fusion, explain why this statement is true.

4. Do you believe nuclear power is a good form of energy? Explain two arguments that support your position and one argument that does not support your position.

Chem A Unit Page 38 Chem A Unit Page 39 4.6 Cloud Chamber Lab Tuesday, March 17, 2020 11:30 AM

Introduction: Radioactivity is often thought of as scary and rare, when in reality it is happening around us all the time! Th ere is a way to actually SEE that atoms are breaking apart. It is called a cloud chamber.

How to Build a Cloud Chamber!

Once you have a cloud chamber, you can put a radioactive material in it and actually collect evidence of what it looks like! You don't need to look far. A simple banana piece would be enough to see decay.

Cloudylabs cloud chamber working approx 50 min [720p]

Note: this video is very long, but you only need to watch a few minutes to collect your data.

Analysis: 1. From the video, you should be able to see THREE different paths. Two of them look very similar, but if you look closely, y ou'll see that their trails are a bit different. Pay attention to how far they travel, how big the paths seem, and how straight the paths are. Record in words the paths you see, then draw them in the circle starting at the middle X:

Written Description A B x C

2. Which type of tracks tend to be the farthest from the source? 3. Why do you think that is? 4. The Cloud Chamber in the video above is zoomed in, but you WOULD be able to see the tracks with your naked eye. What does thi s tell you about how scientists can study forms of nuclear change? 5. The object in the video could be something as simple as a banana bought from a grocery store. What does this tell you about n uclear decay? Should we always be afraid of nuclear changes?

Chem A Unit Page 40 4.7a Alpha and Beta Decay Phet Tuesday, March 17, 2020 11:30 AM

Part 1: Alpha Decay Instructions: I. Web search “alpha decay phet” or go to https://phet.colorado.edu/en/simulation/alpha-decay (This phet is a java phet. If you can not get it to open, please see the videos at the very bottom of this assignment.) II. Click on “Single Atom” III. Pick Polonium-211 nucleus IV. Run the simulation FOUR times

Answer the following: 1. Write the atom you are beginning with in atomic symbol notation:

2. After the alpha decay, what atom are you left with? Write it in atomic symbol notation:

3. Which element has the same protons as the particle emitted from alpha decay? Write it in atomic symbol notation as well.

4. Use the answers from 1-3 to write the equation for this nuclear reaction:

5. Describe with words and draw alpha decay:

6. Now pay attention to the energy of the atom as decay occurs. The atoms starts with more energy and the moment decay happens, the energy drops. Why do you think this energy change happens?

7. Why are the protons and neutrons vibrating?

8. What flew off during decay?

9. Why do you think this occurred?

10. Based on your observations, would you say a STABLE or UNSTABLE atom has more energy? Explain your reasoning.

Chem A Unit Page 41 10. Based on your observations, would you say a STABLE or UNSTABLE atom has more energy? Explain your reasoning.

Part 2: Beta Decay Instructions: web search “beta decay phet” or go to https://phet.colorado.edu/en/simulation/beta-decay

Answer the following: 12. Select the Hydrogen-3 isotope and write the atomic symbol notation for it:

13. Write the resulting isotope in symbol notation:

14. Write the nuclear equation for beta decay: ______à ______+ ______+ antineutrino + Gamma Radiation

15. Select the Carbon-14 isotope and write the atomic symbol notation for it:

16. Write the resulting isotope in symbol notation:

17. Write the nuclear equation for this beta decay: ______à ______+ ______+ antineutrino + Gamma Radiation 18. Describe in words and draw beta decay:

Part 3: Practice Problems Alpha Decay: 19. DRAW Pu going through alpha decay.

20. Why did Pu go through alpha decay?

21. Write 3 equations of elements going through alpha decay. Try to push yourself by using the Band of Stability (4.3b) to pick elements that are naturally radioactive already (white boxes). 174 4 170 Example: 79 Au à 2 He + 77 Ir + gamma radiation

a. ______à ______+ ______+ Gamma Radiation b. ______à ______+ ______+ Gamma Radiation c. ______à ______+ ______+ Gamma Radiation

Beta Decay: 22. DRAW Li going through beta decay.

Chem A Unit Page 42 22. DRAW Li going through beta decay.

23. Why did Li go through beta decay?

24. Write 3 equations of elements going through alpha decay. Try to push yourself by using the Band of Stability (4.3b) to pick elements that are naturally radioactive already (white boxes). 170 0 170 Example: 69 Tm à -1 e + 70 Yb + antineutrino + gamma radiation a. ______à ______+ ______+ antineutrino + Gamma Radiation b. ______à ______+ ______+ antineutrino + Gamma Radiation c. ______à ______+ ______+ antineutrino + Gamma Radiation

Video Alternatives (if java isn't able to be opened on your computer): Alpha Decay: Simulation

Beta Decay: Simulation

Chem A Unit Page 43 Chem A Unit Page 44 4.7b Alpha/Beta Practice Tuesday, March 17, 2020 11:31 AM

Directions: You will be looking at two types of radioactive decay – alpha decay (α) and beta decay (β). Fill in the table below and then use it to help you figure out what is happening during each type of decay.

Fill in the table below using the equations given.

Equatio Change in atomic Number of protons lost or Number of neutrons lost or Change in mass Alpha or Beta n number gained gained number decay? 1 Lost 2 Alpha 2 Lost 2 3 4 Minus 4 5 Plus 1 Beta

Answer the following questions: 1. What changes take place in the nucleus when an alpha particle is emitted (released)?

2. What element or subatomic particle is an "Alpha Particle"?

3. What changes take place in the nucleus when a beta particle is emitted?

4. What element or subatomic particle is a "Beta Particle"?

5. When an alpha particle is lost from an atom, where on the periodic table would you look to find the product? To the left or right of the initial atom?

6. Fill in the missing parts of the nuclear reactions below: a. Bottom: __, ?: ___ b. Top: __, Bottom: __, ?: ____ c. Top: __, Bottom: __, ?: ____ d. Top: __, Bottom: __, ?: ____ e. ?: ____ f. ?: ____

7. Does the identity of the atom change during radioactive decay? Why or why not?

8. If an atom of element number 85, astatine, undergoes alpha decay, what atom will be produced?

9. If an atom of element number 87, francium, undergoes beta decay, what atom will be produced?

10. Which isotopes are most likely to decay?

Chem A Unit Page 45 4.7c Alpha/Beta Articles Wednesday, March 18, 2020 1:26 PM

Reading 1: COSTS of exposure to alpha/beta decay

The Effects of Radiation on Matter Introduction There are many types of radiation, but the two most common are electromagnetic radiation and ionizing radiation. Ionizing radiation refers to radioactive particles, such as alpha and beta particles, or electromagnetic waves, such as gamma or ultraviolet rays, which have sufficient energy to detach electrons off of atoms to create ions, hence the name “ionizing radiation.” Electromagnetic radiation, which sometimes can be placed as a subcategory of ionizing radiation, deals with waves or photons from the electromagnetic spectrum. Unlike ionizing radiation, electromagnetic radiation deals with electric and magnetic field oscillations such as with X-rays, radio waves, or gamma rays.

Radioactive decay of atoms creates three radioactive particles, alpha, beta, and gamma. Of the three, alpha particles are known to have the most “ionizing power,” a term describing the number of ion pairs produced per centimeter through a material, followed by beta, then gamma. However, a common misconception is that the higher ionizing power a particle has, the more damaging it is to matter. Electromagnetic waves can also ionize, hence the reason electromagnetic radiation is often placed as part of ionizing radiation. Penetration and Radiation Radiation, besides having the ability to ionize matter, can also penetrate through matter. How far they penetrate is dependent on the different types of radiation and their ionizing power. Since alpha particles are high in ionizing power, it is difficult for them to penetrate matter thoroughly. This is because alpha particles are likely to ionize the first thing they come into contact with; thus, they hold a small range of penetrating power. The inverse relation between ionizing power and penetrating power can be applied to beta and gamma rays as well. Alpha particles can be stopped with a sheet of paper or a layer of clothing, while beta particles can penetrate up to a fraction of an inch in solids and liquids and several feet in air. Gamma rays, which are electrically neutral and have small ionizing power, are not slowed by collisions with materials and can only be stopped with heavy metals such as lead.

(Courtesy of Ehamberg and Stannered on Wikimedia Commons, available under Creative Commons Attribution 2.5 Generic license.)

Effects of Radiation on Living Matter

Chem A Unit Page 46 Prolonged exposure to radiation often has detrimental effects on living matter. This is due to radiation’s ionizing ability, which can damage the internal functioning of cells. Radiation either ionizes or excites atoms or molecules in living cells, leading to the dissociation of molecules within an organism. The most destructive effect radiation has on living matter is ionizing radiation on DNA. Damage to DNA can cause cellular death, mutagenesis (the process by which genetic information is modified by radiation or chemicals), and genetic transformation. Effects from exposure to radiation include leukemia, birth defects, and many forms of cancer. Most external radiation is absorbed by the environment; for example, most ultraviolet radiation is absorbed by the ozone layer, preventing deadly levels of ultraviolet radiation to come in contact with the surface of the earth. Sunburn is an effect of UV radiation damaging skin cells, and prolonged exposure to UV radiation can cause genetic information in skin cells to mutate, leading to skin cancer. Alpha, beta, and gamma rays also cause damage to living matter, in varying degrees. Alpha particles have a very small absorption range, and thus are usually not harmful to life, unless ingested, due to its high ionizing power. Beta particles are also damaging to DNA, and therefore are often used in radiation therapy to mutate and kill cancer cells. Gamma rays are often considered the most dangerous type of radiation to living matter. Unlike alpha and beta particles, which are charged particles, gamma rays are instead forms of energy. They have large penetrating range and can diffuse through many cells before dissipating, causing widespread damage such as radiation sickness. Because gamma rays have such high penetrating power and can damage living cells to a great extent, they are often used in irradiation, a process used to kill living organisms.

Reading 2: BENEFIT of using Alpha Decay in Smoke Detectors About Americium in Smoke Detectors Smoke detectors are common household items. Ionization smoke detectors use a small amount of radioactive material, americium-241, to detect smoke. Alpha particles from the americium source ionize air molecules, allowing positive and negative ions to flow between charged plates in the smoke detector. The smoke alarm triggers when smoke particles disrupt the constant flow of ions. If you use the smoke detector as directed and do not tamper with it, there is no radiation health risk.

Chem A Unit Page 47 There is no health threat from ionization smoke detectors as long as the detector is not tampered with and it is used as directed. The tiny amount of americium used is encased in ceramic and foil. There are no special disposal instructions for ionization smoke detectors. They may be thrown away with household trash, however your community may have a separate recycling program.

Chem A Unit Page 48 4.8a Half Life Lab Tuesday, March 17, 2020 11:31 AM Purpose: Simulate the transformation of a radioactive isotope over time Graph the data to define half-life.

Background: Unstable isotopes become more stable atoms. To do this, they undergo radioactive decay. Each atom has a different rate of radioactive decay that can occur. During this simulation we will discover about how much of each atom undergoes decay each time the reaction happens.

Materials: Container of 100 coins (representing the radioactive isotope) – Tailium (T) paper clips (representing the new stable atom) – Paperclipium (Pp)

Pre-Laboratory Questions:

1. What is an isotope? Give one example.

2. What causes an atom to undergo radioactive decay?

If you have physical supplies (100 pennies and paper clips) If you don't have the physical materials Procedure: Procedure:

1. Put the paperclips to the side. These are the stable atom Paperclipium (Pp) 1. Go to https://www.random.org/coins/ 2. Turn all the coins to tails and count the total number of the coins. Record 2. Set the coin number to 100 and select any coin (preferrably one with obvious in data table at time zero. heads/tails) 3. Put all the coins in the cup. These are all radioactive (unstable) atoms 3. These are all radioactive (unstable) atoms called Tailium (T) called Tailium (T) 4. Select "Flip Coins" 4. Shake all the coins gently. 5. Count all the coins that are heads up 5. After 30 seconds pour the sample out onto the lab table. This represents 1 6. These are all the coins that have now decayed and become Paperclipium year. 7. Record how many Tailium are remaining after 1 year. Record how many 6. Separate the sample into heads and tails and count the tails – these are still Paperclipium there are now. Tailium. Record the numbers in data table. Place ONLY these back into 8. The remaining coins need to be flipped again – go back to the previous screen. the container. 9. Set the number of coins to flip as the number of Tailium you had remaining. 7. Any coin that is heads up is now Paperclipium, so put them to the side and (for example, if 47 coins were heads, 100-47=53. You would set the number to replace them with paperclips. 53) 8. Add the paper clips to the container to bring the number of objects back to Repeat steps 2-9 until there are zero Tailium Remaining. the starting number (the total number of atoms should NOT change). 10. Shake gently. 11. Complete the calculations on the data table for individual and class results. 9. Repeat steps 4 through 8 until no Tailium is left (all coins are paperclips). 12. Graph the amount of Tailium left after each half life on the graph for your data and the class data. 10. Complete the calculations on the data table for individual and class results. 11. Graph the amount of Tailium left after each half life on the graph for your data and the class data.

Remember that Tallium doesn't just disappear. It becomes a new element through decay (Paperclipium)

Data Table:

Trial # Years Tailium Paperclipium % Tailium remaining 0 0 100 0 100% 1 1 2 3 4 5

Chem A Unit Page 49 5 6 7 8 9 10

3. Half-Life: How many years did it take Tailium to only have 50% remaining? ______

Graph your data:

Below is a graph of class data collected last year.

Analysis:

1. How did your data compare to the class data?

Chem A Unit Page 50 2. What did the pennies that landed as tails represent?

3. Why were the pennies that landed as heads removed and replaced by paperclips?

4. At what point on the graph is there only half of the Tailium remaining? Where did it go?

5. How long did it take for Tailium to go from 50% remaining to 25% remaining?

6. 25% is HALF of 50%. What do you notice about the time it took for 50% of Tailium to change compared to how long it took for Tailium to lose half again (50%-25%).

7. How long did it take for Tailium to go from 25% remaining to 12.5% remaining?

8. Did the amount of time it take for Tailium to decay by 50% change or stay the same?

Conclusion:

9. Use questions 4-5 to select the correct definition of “half-life”? a. When there is only half of the element remaining b. The amount of time it takes for half of a sample to decay into a new element c. The amount of time it takes for half of a sample to disappear d. The amount of time it takes for a sample to completely decay into a new element

10. Explain your answer to 9.

11. Is half-life a measurement of time or amount? Explain your answer.

Three Students analyze the data on the graph below based on this lab: Time (days) Amount of Substance A (g) Amount of Substance B (g) Percent of A remaining 0 1000 0 100 1 700 300 70 2 500 500 50 3 350 650 35 4 250 750 25 5 175 825 17.5 6 125 875 12.5 7 87.5 912.5 8.75 8 62.5 937.5 6.25

Student A: The half-life of Substance A must be 1 day because that is when data was recorded. Student B: I disagree, the half-life must be 2 days because that is when 50% of Substance A is now Substance B. Student C: I think the half-life is 500g because that is half of what Substance A started with.

12. Which student do you agree with and why?

13. Confirm your ideas by watching the video at the very bottom of this page. Note: do not worry too much about the math!

Exponential Decay: Penny Experiment

Chem A Unit Page 51 GCSE Physics - Radioactive Decay and Half Life #35

Chem A Unit Page 52 4.8b Half Life Notes and Problems Tuesday, March 17, 2020 11:31 AM To fill in the notes, be sure to watch the video at the very bottom of the page on 4.8a. 1. Half-life: The time it takes for the amount of a radioactive isotope to decrease by ______. This varies considerably between different atoms. 14 a. Half-life of C = 5,730 years 238 b. Half-life of U = 4.5 billion years 2. After an atom goes through decay, it doesn’t just disappear. This means when half the Carbon-14 atoms have gone through beta decay, they’re not gone – they are now ______. Hint: look back at your equations for beta decay (4.7b) to figure out the new element. Answer these questions using the graph below:

3. The number of grams present in the original sample of sodium-24 is ______. (don’t forget units!) 4. The half-life of sodium-24 is ______. (don’t forget units!) 5. After 30 hours, ______of sodium-24 are present. 6. After 45 hours, about ______is present. 7. If the sample has 125 g of sodium-24 left, then ______has passed.

Chem A Unit Page 53 Half Life Practice Note: Half-life is the amount of time it takes for half of the mass of an unstable atom to decay. Directions: These problems are both practice with half-life and giving some costs/benefits of using radioactivity. Be sure you are paying attention to the uses of half-life as well as how to calculate it.

1. Iodine-131 is used to destroy thyroid tissue in the treatment of an overactive thyroid. The half-life of iodine-131 is 8 days. If a hospital receives a shipment of 200 g of Iodine 131, how much I-131 would remain after 32 days? Trials Half-life (t) Mass Percent To figure out percent (this works for grades too!): Mass Remaining ÷ Total Mass x 100 0 0 200g 100% 1 8 days 100g 50% 2 16 days 3 24 days 4 32 days

2. Iodine primarily goes through Beta Decay when it decays. What element is 50% of the Iodine-131 atoms after 8 days? ______

3. Technetium-99 is used for brain scans. If a laboratory receives 200g of this isotope and after 24 hours only 12.5 g of this isotope remain, what is the half-life of technetium-99? Trials Half-life (t) Mass Percent 0 0 200g 100% 1 50% 2 25% 3 12.5% 4 24 hours 12.5g 6.25%

4. Technetium-99 primarily releases gamma radiation as it decays. This means that after 24 hours, 187.5 grams the atoms of Technetium-99 are still ______, but not giving off gamma radiation.

5. Mercury-197 is used for kidney scans and has a half-life of 3 days. If the amount of mercury-197 needed for a study is 1.0 gram and the shipment time is 15 days, what is the minimum mass of mercury-197 that needs to be ordered? Trials Half-life (t) Mass Percent 0 0 100% 1 3 days 50% 2 6 days 25% 3 9 days 12.5% 4 12 days 6.25% 5 15 days 1.0g 3.125%

6. Mercury-197 goes through a different kind of beta decay where a proton becomes a neutron. This means that after 15 days, most of the atoms in the sample would be ______.

7. The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g? Trials Half-life (t) Mass Percent

Chem A Unit Page 54 Trials Half-life (t) Mass Percent 0 0 4.0g 100% 1 25 years

8. Strontium-90 goes through beta decay. This means that after 100 years, most of the sample will now be ______.

9. The isotope H-3 has a half life of 12.26 years. Find the percent remaining after approximately 49 years. Trials Half-life (t) Percent 0 0 100% 1 12.26 years 2 24.52 years

10. Hydrogen-3 also goes through beta decay. This means it becomes ______when it decays.

11. How long will it take for 64.0g of Rn-222 (half-life = 3.8235 days) to decay to 8.00g? Trials Half-life (t) Mass Percent 0 0 64.0g 100% 1 3.8235 days

12. Radon-222 goes through alpha decay. This means that the “missing” 56g has actually become ______.

13. Silicon-31 has a half-life of approximately 2.5 hours. If we begin with a sample containing 1000 mg of Si-31, what is the approximate amount remaining after 10 hours? Trials Half-life (t) Mass Percent 0 0 1000mg 100% 1 2.5 hours

14. Silicon-31 goes through beta decay to become ______as it decays.

15. Cesium-137 was the long lived isotope released during the Chernobyl explosion in Russia that killed 60 people immediately, and potentially another 4000 due to radiation. Cesium has a half-life of 30 years and the reactor released 80,000 KBq. Chernobyl will only be safe to live in again if the levels are less than 1000KBq (less than 1.25% of original amount). Trials Half-life (t) Mass Percent 0 0 80,000 KBq 100%

Chem A Unit Page 55 0 0 80,000 KBq 100% 1 30 years

16. How long until Chernobyl is livable again (be sure to read question 15 closely)? ______

17. Cesium-137 also goes through beta decay. This means after one half life, 50% of the cesium will now be ______.

Chem A Unit Page 56 SIR PART 3: Types of Decay and Half-Life Monday, March 23, 2020 11:27 AM

Chem A Unit Page 57 Chem A Unit Page 58 Chem A Unit Page 59 Chem A Unit Page 60 Chem A Unit Page 61 Answer the questions below:

Chem A Unit Page 62 1. If I wanted to create thorium-200, would you expect that element to be stable? Why or why not?

2. Why would gamma radiation be considered more dangerous than alpha or beta radiation?

3. Complete the following nuclear equations:

a.

b.

c.

4. Complete the following half-life questions. A. Os-182 has a half-life of 21.5 hours. Fill out the following table to figure out how much Os-182 I started with to end up with 10 g after 107.5 hours. Mass ½-life Time

B. The half-life of Zn-71 is 2.4 minutes. If I start with 100g, how much is left after 7.2 minutes? Show your work.

Chem A Unit Page 63 4.9 Nuclear Science Final Debate Tuesday, March 17, 2020 11:31 AM

For your final ideas on this issue, use your Learning Tracking Tool and what you have learned to debate with your classmates.

You will need to go onto schoology and find the "4.9 Final Nuclear Sciences Debate" discussion to add your comment.

Before you do, prepare by answering the questions here first.

Prep Questions:

1. What did you learn about why atoms go through nuclear change? 2. How are radioactive elements both dangerous and helpful? 3. What is fission? 4. What is fusion? 5. How are fission and fusion both dangerous and helpful? 6. What is alpha decay? 7. What is beta decay? 8. What is half-life? 9. How are different types of decay dangerous or helpful?

Discussion Question: Your Argument: Is the pursuit of nuclear science beneficial to society or are the costs too great? Be sure to include an explanation as well as at least 2 pieces of evidence.

After answering the question above in the Schoology discussion, you will then need to respond to AT LEAST 2 other students. One response must be an ARGUMENT AGAINST their point.

Expectations: 1. Clearly stated instruductory sentence 2. Explanation of reasoning with at least 2 different points 3. At least 2 pieces of evidence from articles or videos is included 4. At lesat 2 responses to other students 5. Responses are clearly written and include at least 1 piece of evidence from articles/videos 6. Responses are CIVIL and NICE

Chem A Unit Page 64 Learning Tracking Tool Tuesday, March 17, 2020 11:31 AM Has the pursuit of Nuclear Science benefited or harmed society?

Lesson What did we figure out? Drawing simple models of How does this add to our How does this add to our Self-Assess: What questions do I have? Summarize key information and nuclear change. argument of the COSTS of argument of the BENEFITS of Where am I with my understanding of What additional information do activities with a description and/or For each reaction, try to nuclear sciences? nuclear sciences? the phenomenon? you need to understand the picture. draw a simple diagram of Identify any con arguments Identify any pros arguments (Example: Ready to debate both sides phenomenon? the change you discovered from this you discovered from this using scientific reasoning, starting to get activity. activity. it, need more information)

4.1 Nuclear Phenomenon We watched a video about the nuclear NO DRAWING NEEDED bombings in Japan and read some possible uses of nuclear sciences. No additional information needed. 4.2 Isotopes - How is the atomic mass The mass on the periodic table is a NO DRAWING NEEDED NO ARTICLES FOR THIS NO ARTICLES FOR THIS calculated? decimal because... ACTIVITY ACTIVITY 4.3 Band of Stability - What types of If elements are outside the band of NO DRAWING NEEDED isotopes exist in nature? stability because of an imbalance of protons and neutrons, it will... 4.4 Fission Phet - How is the atomic Fission is... Draw fission: number and mass affected by fission? How is energy related? The atomic mass will...

The atomic number will...

The number of atoms coming out of the reaction is (greater/less) than the number of atoms that went into the reaction. 4.5 Fusion Activity - How is the atomic Fusion is... Draw fusion: number and mass affected by fusion? The atomic mass will...

The atomic number will...

The number of atoms coming out of the reaction is (greater/less) than the number of atoms that went into the reaction.

4.6 Cloud Chamber Lab - What evidence Nuclear change is (common/uncommon) NO DRAWING NEEDED NO ARTICLES FOR THIS Radioactive decay is naturally led to different forms of nuclear decay? and there (is/is not) evidence of decay. ACTIVITY occurring

4.7 Alpha and Beta Decay - How can we Alpha decay is... Draw Alpha Decay: model alpha and beta decay? How do they change the atom? The atomic mass will...

The atomic number will...

The particle that is ejected is...

Beta decay is... Draw Beta Decay: The atomic mass will...

The atomic number will...

The particle that is ejected is...

4.8 Half Life - At what rate do atoms Half life is defined as... NO DRAWING NEEDED decay? How can we use that information?

When an element is decaying, it is (disappearing/not disappearing). It is...

Chem A Unit Page 65 4.2 Isotopes Tuesday, March 17, 2020 11:23 AM

Pre Activity questions: 1. What is an isotope?

Atom Protons Electrons Neutrons A 3 3 4 B 3 2 3

2. Examine the table above - are the atoms A and B of the same element? Explain how you know.

Lab Objective: Why is there a decimal for the mass of elements on the periodic table?

Below is a data set for a same of hydrogen atoms. A 1 gram sample of hydrogen was evaluated for all the different types of isotopes within the sample:

Isotopes Found Hydrogen-1 Hydrogen-2 Hydrogen-3 Atomic Mass 1 AMU 2 AMU 3 AMU Total mass within 1g sample 0.99g 0.099g 0.001g Percent of total mass 99% 0.99% 0.01%

3. The atomic mass recorded on the periodic table for Hydrogen is 1.01 AMU. Notice that each isotope of Hydrogen is ALWAYS a whole number. Where do you think the decimal came from looking at the data above?

The mass on the periodic table is called a WEIGHTED AVERAGE. This means that the mass is not of a single atom, but it is the average of all possible isotopes found of that atom. To calculate weighted average, you take the mass of each isotope, multiply it by the percent of the sample it makes up, and then add them together. Divide this number by 100 and you get the AVERAGE ATOMIC MASS.

(99 X 1) + (.99 X 2) + (.01 X 3) = 101 ÷ 100 = 1.01 AMU

4. Using the above paragraph, explain why the mass on the periodic table is a decimal.

5. For hydrogen, which isotope is closest to the mass recorded on the periodic table? Why do you think this is based on the data for hydrogen?

Below is the data set for a sample of Carbon

Isotopes Found Carbon-12 Carbon-13 Carbon-14 Other Isotopes Atomic Mass 12 AMU 13 AMU 14 AMU Various Total Mass within 1g sample 0.99g 0.009 0.0009 0.0001g Percent of total mass 99% 0.9% 0.09% 0.01%

6. Based on the data above, which of these would most likely be the recorded mass of Carbon on the periodic table? a. 12 b. 12.01 c. 13

Homework Page 66 c. 13 d. 13.01 e. 14 f. 14.01

7. Explain your answer to 6:

8. If you had 1000 carbon atoms and pulled out just one atom, what would its mass most likely be?

9. Explain your answer to 8:

10. Based on the average atomic mass on the periodic table, examine the 3 isotopes of Sulfur. a. Fill in the table below comparing the 3 isotopes.

Protons Electrons Neutrons Mass

b. If were able to separate out a single sulfur atom from a 1g sample, how many neutrons would you expect it to have? Explain your answer using the mass on the periodic table.

The chart below shows the isotopes that exist for the first six elements. Use the chart and a periodic table to answer questions 11 and 12.

Homework Page 67 11. How many isotopes does hydrogen have? How are they different from each other?

12. Fill in the bolded boxes with the isotope symbol for the isotopes of lithium, beryllium, and boron. You may have to use the drawing tool. Or you could create a text box and drag it over.

Use the Isotopes of Elements Chart (4.3b) to answer questions 13-15 13. Give the isotope name and symbol of the only naturally occurring isotope of phosphorus.

14. Which element has the most isotopes? How many isotopes does this element have?

15. Find Tin (50) a. Fill in the top box with the isotope symbol and isotope name for 3 possible isotopes.

Homework Page 68 a. Fill in the top box with the isotope symbol and isotope name for 3 possible isotopes. b. Determine number of protons, electrons, neutrons and mass for each isotope. c. Circle the isotope that you would mostly like have if you managed to isolate a single atom of tin.

Protons Electrons Neutrons Mass

Additional Practice Use the phet below and play around with the Mixtures tab. You should be able to answer these two questions when you finish: 16. Explain why the periodic table has a decimal:

17. Determine the most common isotope of elements based on the number on the period table:

Isotopes and Atomic Mass

Homework Page 69 Homework Page 70 4.2 Isotopes Tuesday, March 17, 2020 11:23 AM

Pre Activity questions: 1. What is an isotope? Two atoms that are the same element (same number of protons), but different masses

Atom Protons Electrons Neutrons A 3 3 4 B 3 2 3

2. Examine the table above - are the atoms A and B of the same element? Explain how you know. Yes! They have the same number of protons (3 = Lithium)

Lab Objective: Why is there a decimal for the mass of elements on the periodic table?

Below is a data set for a same of hydrogen atoms. A 1 gram sample of hydrogen was evaluated for all the different types of isotopes within the sample:

Isotopes Found Hydrogen-1 Hydrogen-2 Hydrogen-3 Atomic Mass 1 AMU 2 AMU 3 AMU Total mass within 1g sample 0.99g 0.099g 0.001g Percent of total mass 99% 0.99% 0.01%

3. The atomic mass recorded on the periodic table for Hydrogen is 1.01 AMU. Notice that each isotope of Hydrogen is ALWAYS a whole number. Where do you think the decimal came from looking at the data above? The different isotopes cause the decimal

The mass on the periodic table is called a WEIGHTED AVERAGE. This means that the mass is not of a single atom, but it is the average of all possible isotopes found of that atom. To calculate weighted average, you take the mass of each isotope, multiply it by the percent of the sample it makes up, and then add them together. Divide this number by 100 and you get the AVERAGE ATOMIC MASS.

(99 X 1) + (.99 X 2) + (.01 X 3) = 101 ÷ 100 = 1.01 AMU

4. Using the above paragraph, explain why the mass on the periodic table is a decimal. Each element has different isotopes and the mass is the average of all of them

5. For hydrogen, which isotope is closest to the mass recorded on the periodic table? Why do you think this is based on the data for hydrogen? Hydrogen-1. It is like this because there is so much Hydrogen-1 compared to the other samples. Average will be closer to the most abundant isotope.

Below is the data set for a sample of Carbon

Isotopes Found Carbon-12 Carbon-13 Carbon-14 Other Isotopes Atomic Mass 12 AMU 13 AMU 14 AMU Various Total Mass within 1g sample 0.99g 0.009 0.0009 0.0001g Percent of total mass 99% 0.9% 0.09% 0.01%

Chem A Unit ANSWER KEYS (not for students) Page 71 6. Based on the data above, which of these would most likely be the recorded mass of Carbon on the periodic table? a. 12 b. 12.01 c. 13 d. 13.01 e. 14 f. 14.01

7. Explain your answer to 4: It wouldn't be exactly 12 because there are multiple isotopes. It will be very close to 12 because most atoms are carbon-12

8. If you had 1000 carbon atoms and pulled out just one atom, what would its mass most likely be? Carbon-12

9. Explain your answer to 6: Because 99% of carbon atoms are this isotope.

10. Based on the average atomic mass on the periodic table, examine the 3 isotopes of Sulfur. a. Fill in the table below comparing the 3 isotopes.

P 16 16 16 E 16 16 16 N 16 17 18 M 32 33 34

b. If were able to separate out a single sulfur atom from a 1g sample, how many neutrons would you expect it to have? Explain your answer It would most likely have 16 because the mass on the periodic table is 32.065 which is closest to Sulfur-32

The chart below shows the isotopes that exist for the first six elements. Use the chart and a periodic table to answer questions 9 and 10.

11 5B Boron-11 9 10 4Be 5B

Chem A Unit ANSWER KEYS (not for students) Page 72 11 5B Boron-11 9 10 4Be 5B Beryllium-9 Boron-10

7 3Li Lithium-7 6 3Li Lithium-6

11. How many isotopes does hydrogen have? How are they different from each other? 3 – they have different numbers of neutrons 12. Fill in the bolded boxes with the isotope symbol for the isotopes of lithium, beryllium, and boron. You may have to use the drawing tool. Or you could create a text box and drag it over.

Use the Isotopes of Elements Chart in the Content Library to answer questions 13-16 13. Give the isotope name and symbol of the only naturally occurring isotope of phosphorus. 31 Phosphorus-31 15P 14. Which element has the most isotopes? How many isotopes does this element have? Sn, Tin – 10 isotopes

15. Find Tin (50) a. Fill in the top box with the isotope symbol and isotope name for 3 possible isotopes. b. Determine number of protons, electrons, neutrons and mass for each isotope. c. Circle the isotope that you would mostly like have if you managed to isolate a single atom of tin.

Tin-112 Tin-114 Tin-120 Possible Isotopes: Tin-112, Tin-114-120, Tin-122, Tin-124 P 50 50 50 E 50 50 50 Tin Atomic Mass: 118.7, so they should circle the N 62 64 70 isotope closest M 112 114 120

Chem A Unit ANSWER KEYS (not for students) Page 73 Additional Practice Use the phet below and play around with the Mixtures tab. You should be able to answer these two questions when you finish: 16. Explain why the periodic table has a decimal: Each element has multiple naturally occuring isotopes and the number on the periodic table is the weighted average of those isotopes.

17. Determine the most common isotope of elements based on the number on the period table: The most common isotope is the closest mass to that recorded on the periodic table.

Isotopes and Atomic Mass

Chem A Unit ANSWER KEYS (not for students) Page 74 4.3a Band of Stability Tuesday, March 17, 2020 11:25 AM

Objective: Determine if an atom is stable, unstable (aka radioactive), or does not exist based on the Isotopes graph. Background Info: Isotopes of elements found in nature are all located within the band of stability on the graph (4.3b). Those elements found in the middle of the band have a very stable nucleus, while those elements on the outer edges of the band have an unstable nucleus and are said to be radioactive. However, some combination of protons and neutrons in the nucleus are so unstable that they cannot even exist long enough to be recognized as elements and these fall outside the band of stability. Instructions: a) determine the number of subatomic particles for each element at the top of the next page. b) locate where the atoms would be on the graph. c) label each atom after it has been plotted (see Potassium-41 as an example)

Questions to Answer NOTE: You will need to use the 4.3b Isotopes of Elements graph to complete this assignment

1. For the elements below, identify how many protons, neutrons, and electrons. Then identify if would be common, radioactive, or non-existent in nature (so radioactive it decays instantly)

# p: 12 # p: 60 # p: 77 # p: 35 # p: 92 # p: 77 # e: 12 # e: 60 # e: 77 # e: 35 # e: 92 # e: 77 # n: 12 # n: 82 # n: 118 # n: 46 # n: 146 # n: 114 Common Common Common Common Common Common Radioactive Radioactive Radioactive Radioactive Radioactive Radioactive Non-Existent Non-Existent Non-Existent Non-Existent Non-Existent Non-Existent

2. Were there any atoms not already plotted on the graph? What does it mean if they are not on the graph? Yes – they are so unstable they don't exist long enough to be considered a natural element (Ir-195)

3. How can there be two different atoms of iridium? How are they different? They are isotopes, different neutron amounts

4. Would a small atom (less than 40 protons) be found in nature if it has the same number of protons and neutrons (1:1 ratio)? Explain. (see the video below if you need extra information)

Yes. On the band of stability below 40 protons, the number of neutrons and protons are equal.

5. Would a large atom (more than 40 protons) be found in nature if it has the same number of protons & neutrons (1:1 ratio)? Explain. No. As the protons increase, the number of neutrons become more than the number of protons.

6. Imagine a chemist was trying to create an atom with 60 protons and a mass number of 155. Would this be possible? Why or why not? (Show where it would fall on the graph.) Yes! A MASS number of 155 means 85 neutrons. It would fall directly in the middle of the band of stability.

7. If an element had 90 protons, how many neutrons would be a good number for it to have in order to be considered a stable element? What element would this be? (Show where It would fall on the graph.) 142 neutrons. It would be Thorium-232

Chem A Unit ANSWER KEYS (not for students) Page 75 142 neutrons. It would be Thorium-232

Stable & Unstable Nuclei | Radioactivity | Physics | FuseSchool

Chem A Unit ANSWER KEYS (not for students) Page 76 SIR PART 1: Nucleus of the Atom Monday, March 23, 2020 11:26 AM

Chem A Unit ANSWER KEYS (not for students) Page 77 Answer the questions below:

1. Calculate the atomic mass of boron if it has the following distribution in a sample of 100 atoms: (20 atoms are boron-10, 80 atoms are boron-11). Show your work. .2 x 10 + .8 x 11 = 10.8

2. The atomic mass of chlorine is 35.45 amu. Why is this number not a whole number? The number is the weighted average of all the isotopes of chlorine atoms

3. Describe 2 different ways that the nucleus of an atom could change? The mass could change - number of neutrons decrease/increase The atomic number could change - number of protons decrease/increase

Chem A Unit ANSWER KEYS (not for students) Page 78 4. Scientists who study the creation of new elements must take a lot of safety precautions. Why is that? Radioactive decay can cause cancer and be dangerous to tissue. Creation of new elements releases Gamma Radiation.

Chem A Unit ANSWER KEYS (not for students) Page 79 4.4a Fission Phet Tuesday, March 17, 2020 11:30 AM

Learning Goals: A. Explain the concept of a “chain reaction” in terms of subatomic particles and energy B. Connect the concept of nuclear fission of uranium with a chain reaction. C. Explain how a nuclear reactor works and how a fission reaction is monitored

Phet: https://phet.colorado.edu/en/simulation/nuclear-fission This is a Java phet, so it will need to be downloaded and opened.

If you cannot open the simulation, you may watch this video: https://kcts9.pbslearningmedia.org/resource/nvhe.sci.chemistry.fission/a-fission-chain-reaction/

And use this visualization. If it stops and says "Subscription" just refresh the page and try again. https://www.edumedia-sciences.com/en/media/491-fission

Part 1: “Fission: One Nucleus”

Instructions: i. You will begin on the “one nucleus screen.” ii. You will see a “gun” that will fire a particle at the nucleus. iii. To fire the gun, click on the red circle. iv. To the right of the simulation area you will see the legend of the symbols for the simulation. v. In the chart at the bottom you will see the blue line that represents the potential energy of the nucleus. vi. The gold line represents the total energy of the nucleus/system.

Questions: 1. Write the uranium nucleus being used in the Atomic Symbol Format. 235 92U

2. Fire the particle gun at the nucleus, draw a picture with captions that describes what happens to the nucleus. You may draw here or on your "Unit 4 Drawings and Models" page. Label it "Fission Lab." NOTE: Watch carefully, because you want to describe the process from the time that the particle strikes the nucleus until the nucleus changes. Stable Unstable Products

3. When the nucleus changes, describe everything that comes out. Rubidium, Cesium, 3 neutrons, lots of energy

4. Create a nuclear decay equation for this process. The first part of that equation is written below. The two daughter nuclei formed are Krypton-92 and Barium-141. Note: your equation should show a middle part and an ending, so a second arrow to the equation 236 92 141 1 1 1 92U --> 36Kr + 56Ba + 0N + 0N + 0N

5. Now, pay attention to the chart at the bottom of the simulation. Answer these questions to analyze the graph: a. What happens to the amount of energy in the atom the moment the neutron is added? The energy increases b. Do all the pieces have more or less energy than the Uranium-236? Less c. Why do you think this happens? The atom is very unstable and then the new atoms are more stable

6. Describe what you would do to make U-235 unstable. Add a neutron

Be sure you understand a single atom going through fission before moving on!

Part 2: “Chain Reaction”

Chem A Unit ANSWER KEYS (not for students) Page 80 Instructions: i. Select the “Chain Reaction” tab at the top. ii. Experiment with settings- change them, shoot the neutron gun and watch what happens. iii. Set the initial number of U-235 nuclei to 100

Questions: 7. What happens when you fire the neutron gun? Note: the gun can rotate; grab it to drag it around. The neutrons from one reaction cause the others to go off

8. Explain why this is called a “chain reaction”. One hit leads to another then another then another like dominos

Set the initial number of U-238 nuclei to 100.

9. Explain what happens when you fire the gun and if this is a chain reaction or not. Nothing happens. The initial atom becomes U-239 and does not go through fission.

Set the initial numbers of U-235 nuclei and U-238 nuclei to the numbers in the following table. 10. Record your results of each combination below. Table of Experimentation with Chain Reactions of different Uranium Isotopes U-235 100 70 50 30 0 U-238 0 30 50 70 100 % of 235U fissioned after 1 firing The percentage should decrease as you add more U-238 # firings required to fission all 235U The number should increase N/A

11. What happens to the reaction as the proportion of U-238 nuclei increases? The reaction slows down.

12. If you were trying to design the most efficient fission reactor possible, what ratio of U-235 to U-238 would you want? Explain why. 100:0 so all the atoms explode

Click on the containment vessel box as shown to the right and experiment with adjusting the number of U-235 and U-238 atoms in the vessel. Also experiment with adjusting the size of the containment vessel.

13. What factor(s) affect whether or not the containment vessel explodes / creates a bomb. Explain. Too many U-235

Be sure you understand Chaing Reaction before moving onto the Nuclear Reactor

Part 3: “Nuclear Reactor” Instructions: i. Select the “Nuclear Reactor” tab at the top. ii. Experiment with changing the settings and firing the neutrons and watch what happens.

Note: As the reactor get darker orange in color this indicates that it is approaching meltdown. A meltdown can destroy the reactor and release dangerous nuclear material into the environment.

14. The bar graphs on the right of the display show the “Power Output” and the “Energy Produced”. What is the difference between these two quantities? In your answer, discuss how these two graphs have an influence on the temperature inside of the reactor as shown by the little thermometer next to the reactor. Power output is the immediate release of the reaction. The energy produced is cumulative over time. Power output matches the thermometer. Energy produced does not.

15. Watch the fission reactions closely as they happen. Specifically watch what happens to the loose neutrons after the reaction? a. What happens if the neutrons hit another nucleus? The reaction continues b. What happens if the neutrons hit a control rod? It is absorbed and does not continue the chain reaction c. What might the control rods contain? Explain. They make sure the energy does not get so high that it explodes

16. Compare the chain reaction that occurs when the control rods are inserted further into the reactor versus when they are pulled all/mostly out of the reactor. The chain reaction ends very quickly when they are inserted and can get out of control if they are completely out

Chem A Unit ANSWER KEYS (not for students) Page 81 17. If the purpose of a nuclear reactor in a power plant is to produce energy, why are there control rods? Answer this question using the words: energy, power and temperature. The control rods prevent the amount of energy getting out of control and increasing the power and temperature to the point ofa meltdown

18. Name 2-3 things about the control rods that you would like to know more about in order to understand how they work in a reactor. Why would knowing these things help you to explain how the rods work? Various answers

19. Describe the similarities and differences between a nuclear reactor and a nuclear bomb. Both use chain reactions, but power plants have control rods to prevent explosions.

Watch This Video to answer question 20: PWR Nuclear Power Plant Animation

20. After watching, describe in a short paragraph how heat released from a nuclear reactor turns into electric energy that we can use to live our everyday lives.

The heat causes water to turn to steam which turn turbines to produce electricity

Part 4: Fission Guided Notes

1. Nuclear Fission is the (splitting/combining) of a(n) (stable/unstable) atom into two or more smaller nuclei. 2. An unstable atom is referred to as (radioactive/an isotope) because it will go through decay or fission. 3. For the fission of Uranium, the atom starts as mostly (stable/unstable) but then the atom is hit with a (proton/neutron/electron). 4. During the nuclear reaction, the added particle causes the big atom to now be more (stable/unstable). 5. At the end, there are two smaller, more (stable/unstable) atoms. 6. Nuclear fission releases a (small/large/massive) amount of energy in the form of heat, light, and sound.

7. The left side of the equation above is called the (reactants/products) and the right is called the (reactants/products). 8. The mass in the reactants is (equal to/greater than/less than) the mass in the products. Hint: be sure to add them all up 9. The proton amount in the reactants is: 92, in the products it is: 92. 10. The mass amount in the reactants is: 236, in the products it is: 236. 11. Fission Nuclear Reactors release a massive amount of energy because they cause a chain reaction between many atoms of Uranium.

Chem A Unit ANSWER KEYS (not for students) Page 82 4.5a Fusion Activity Tuesday, March 17, 2020 11:30 AM

Part 1: Fusion in Stars The Most Astounding Fact - Animated

First read this article: https://www.popsci.com/neutron-star-gold/#page-2 Then watch this video: https://www.nytimes.com/2017/10/16/science/ligo-neutron-stars-collision.html?smid=pl-share 1. What did you learn from the videos and article? Various 2. Where do most our heavy elements come from? Processes in stars 3. Would this suggest fusion releases/needs a lot of energy or a little bit of energy? Explain Lots of energy – stars contain and release massive amounts of energy 4. Would these resources suggest that fusion is natural or unnatural? Natural

PART 2: Modeling Nuclear Fusion in Stars MATERIALS 1. 15 White Marshmallows (or one type of candy) 2. 15 Gummy Bears (or another type of candy)

INSTRUCTION FOR CANDY FUSION 1. The materials represent the following: • 1 Gummy Bear = 1 Proton • 1 White Marshmallow = 1 Neutron 2. Use the candies to create the models of: 1H, 2H and 3H shown below, then eat them. Fill in the numbers below each image. 1H 2H 3H

Chem A Unit ANSWER KEYS (not for students) Page 83 Number of Protons in Hydrogen-1: 1 Number of Protons in Hydrogen-2: 1 Number of Protons in Hydrogen-3: 1 Number of Neutrons in Hydrogen-1: 0 Number of Neutrons in Hydrogen-2: 1 Number of Neutrons in Hydrogen-3: 2

3. Create models three identical atoms of Helium-4. Sketch your models, but keep them for the next steps. Each should have two gummy bears and two marshmallows (total of 6 marshmallows and 6 gummy bears)

4. Smoosh all the He atoms together to make one new element. a. What element did you make (count the gummy bears and use the periodic table)? Carbon-12

b. Label it with the appropriate symbol (use isotopic notation format)

12 6C

c. Draw the element Should have 6 protons and 6 neutrons

d. How many protons (in total) were present before the reactions (add all Helium together)? How many were present after the reaction? 6 before and 6 after

e. How many neutrons (in total) were present before the reactions? How many were present after the reaction? 6 before and 6 after

5. What element would you make if you fused another 4He with the carbon atom you created in Step 4? a. Model the reaction (in other words, make it with the candies) b. Draw the product Should draw an element with 8 protons and 8 neutrons

c. Label it with the appropriate symbol. 16 8O

6. What element would you make if you fused another 4He with the oxygen atom you created in Step 5? Neon-20 a. Model it with the candies b. Complete the nuclear equation for the reaction below.

16 4 20 8O + 2He à 10Ne 7. How could you form magnesium from the element you created in Question 6? You could add another Helium-4 to Neon-20 a. Model it b. Write a nuclear equation for the reaction below (remember to use an arrow)

20 4 24 10Ne + 2He → 12Mg

PART 3: Analysis 8. Does nuclear fusion affect the total of the mass numbers before and after the reaction? Cite specific evidence to support your answer.

Chem A Unit ANSWER KEYS (not for students) Page 84 8. Does nuclear fusion affect the total of the mass numbers before and after the reaction? Cite specific evidence to support your answer. No for all equations the added mass on the left (reactants) matched the total mass on the right (products)

9. Does nuclear fusion affect the total of the atomic numbers before and after the reaction? Cite specific evidence to support your answer. No for all equations the added atomic number on the left (reactants) matched the total atomic number on the right (products)

10. In normal function of stars, iron is the heaviest element formed. What is a fusion reaction that could produce 52Fe? Many Various Answers. Probably Chromium + Helium

11. Is energy absorbed or produced by nuclear fusion? (Hint: think about where fusion occurs) Both! Stars give it energy, but energy is released as well

12. What are some limitations of using candies as a model for fusion? Various Answers - mainly we can't see/model energy

Chem A Unit ANSWER KEYS (not for students) Page 85 SIR PART 2: Fission/Fusion and Stability Monday, March 23, 2020 11:26 AM

Chem A Unit ANSWER KEYS (not for students) Page 86 Chem A Unit ANSWER KEYS (not for students) Page 87 Chem A Unit ANSWER KEYS (not for students) Page 88 Chem A Unit ANSWER KEYS (not for students) Page 89 Analysis and reading questions:

1. Describe the difference between fission and fusion. Fission is the splitting of an atom into smaller pieces. Fusion is the combining of atoms into a larger atom.

2. Why are the neutrons released during fission important to a fission chain reaction? The neutrons collide with other atoms making them less stable. This leads to them also releasing neutrons when the split which causes one to split right after another.

3. A common statement from science is, “We are all stardust.” Use your understanding of fusion, explain why this statement is true. All large elements are created in stars because it requires a massive amount of energy. Our body is made of those elements.

Chem A Unit ANSWER KEYS (not for students) Page 90 4. Do you believe nuclear power is a good form of energy? Explain two arguments that support your position and one argument that does not support your position. Various - nuclear power provides lots of energy, but waste is dangerous

Chem A Unit ANSWER KEYS (not for students) Page 91 4.6 Cloud Chamber Lab Tuesday, March 17, 2020 11:30 AM

Introduction: Radioactivity is often thought of as scary and rare, when in reality it is happening around us all the time! Th ere is a way to actually SEE that atoms are breaking apart. It is called a cloud chamber.

How to Build a Cloud Chamber!

Once you have a cloud chamber, you can put a radioactive material in it and actually collect evidence of what it looks like! You don't need to look far. A simple banana piece would be enough to see decay.

Cloudylabs cloud chamber working approx 50 min [720p]

Note: this video is very long, but you only need to watch a few minutes to collect your data.

Analysis: 1. From the video, you should be able to see THREE different paths. Two of them look very similar, but if you look closely, y ou'll see that their trails are a bit different. Pay attention to how far they travel, how big the paths seem, and how straight the paths are. Record in words the paths you see, then draw them in the circle starting at the middle X:

Written Description A Straight line that went far B Straight line that didn't go far x C Squiggly line that went far

2. Which type of tracks tend to be the farthest from the source? Depends on their descriptions above 3. Why do you think that is? Various Answers - looking for "because it must be small" 4. The Cloud Chamber in the video above is zoomed in, but you WOULD be able to see the tracks with your naked eye. What does thi s tell you about how scientists can study forms of nuclear change? We can see the different types of particles released. It is possible to observe nuclear change. Various answers 5. The object in the video could be something as simple as a banana bought from a grocery store. What does this tell you about n uclear decay? Should we always be afraid of nuclear changes? Nuclear decay is common and natural. We don't need to always be afraid of it.

Chem A Unit ANSWER KEYS (not for students) Page 92 4.7a Alpha and Beta Decay Phet Tuesday, March 17, 2020 11:30 AM

Part 1: Alpha Decay Instructions: I. Web search “alpha decay phet” or go to https://phet.colorado.edu/en/simulation/alpha-decay (This phet is a java phet. If you can not get it to open, please see the videos at the very bottom of this assignment.) II. Click on “Single Atom” III. Pick Polonium-211 nucleus IV. Run the simulation FOUR times

Answer the following: 1. Write the atom you are beginning with in atomic symbol notation:

211 84Po

2. After the alpha decay, what atom are you left with? Write it in atomic symbol notation: 207 82Pb

3. Which element has the same protons as the particle emitted from alpha decay? Write it in atomic symbol notation as well.

Helium

4 2He

4. Use the answers from 1-3 to write the equation for this nuclear reaction: 211 207 4 84Po --> 82Pb + 2He + Gamma

5. Describe with words and draw alpha decay: Atom loses a Helium atom. This decreases the mass by 4 and the atomic number by 2. Becomes a smaller, more stable atom.

6. Now pay attention to the energy of the atom as decay occurs. The atoms starts with more energy and the moment decay happens, the energy drops. Why do you think this energy change happens?

The atom becomes more stable

7. Why are the protons and neutrons vibrating? Atom is unstable/radioactive

8. What flew off during decay? Helium

9. Why do you think this occurred? The atom was unstable and broke apart

10. Based on your observations, would you say a STABLE or UNSTABLE atom has more energy? Explain your reasoning. Unstable atoms have more energy because the energy goes down when it becomes more stable

Chem A Unit ANSWER KEYS (not for students) Page 93 Part 2: Beta Decay Instructions: web search “beta decay phet” or go to https://phet.colorado.edu/en/simulation/beta-decay

Answer the following: 12. Select the Hydrogen-3 isotope and write the atomic symbol notation for it:

3 1H

13. Write the resulting isotope in symbol notation:

3 2He

3 3 -1 14. Write the nuclear equation for beta decay: 1H à 2He + e + antineutrino + Gamma Radiation

15. Select the Carbon-14 isotope and write the atomic symbol notation for it: 14 6C

16. Write the resulting isotope in symbol notation: 14 7N

14 14 -1 17. Write the nuclear equation for this beta decay: 6C à 7N + e + antineutrino + Gamma Radiation 18. Describe in words and draw beta decay:

An unstable atom loses an electron. A neutron becomes a proton, so the mass stays the same, but the atomic number increases by 1.

Part 3: Practice Problems Alpha Decay: 19. DRAW Pu going through alpha decay.

20. Why did Pu go through alpha decay? It was unstable/radioactive

21. Write 3 equations of elements going through alpha decay. Try to push yourself by using the Band of Stability (4.3b) to pick elements that are naturally radioactive already (white boxes). 174 4 170 Example: 79 Au à 2 He + 77 Ir + gamma radiation

Various answers, but make sure the mass decreased by 4 and the atomic number by 2 4 a. ______à ______+ 2He + Gamma Radiation 4 b. ______à ______+ 2He + Gamma Radiation 4 c. ______à ______+ 2He + Gamma Radiation

Beta Decay: 22. DRAW Li going through beta decay.

Chem A Unit ANSWER KEYS (not for students) Page 94 23. Why did Li go through beta decay? Unstable/radioactive

24. Write 3 equations of elements going through alpha decay. Try to push yourself by using the Band of Stability (4.3b) to pick elements that are naturally radioactive already (white boxes). 170 0 170 Example: 69 Tm à -1 e + 70 Yb + antineutrino + gamma radiation

Various answers, but make sure the mass stayed the same and the atomic number increased by 1

a. ______à ______+ e-1 + antineutrino + Gamma Radiation b. ______à ______+ e-1 + antineutrino + Gamma Radiation c. ______à ______+ e-1 + antineutrino + Gamma Radiation

Video Alternatives (if java isn't able to be opened on your computer): Alpha Decay: Simulation

Beta Decay: Simulation

Chem A Unit ANSWER KEYS (not for students) Page 95 4.7b Alpha/Beta Practice Tuesday, March 17, 2020 11:31 AM

Directions: You will be looking at two types of radioactive decay – alpha decay (α) and beta decay (β). Fill in the table below and then use it to help you figure out what is happening during each type of decay.

Fill in the table below using the equations given.

Equatio Change in atomic Number of protons lost or Number of neutrons lost or Change in mass Alpha or Beta n number gained gained number decay? 1 Minus 2 Lost 2 Lost 2 Minus 4 Alpha 2 Minus 2 Lost 2 Lost 2 Minus 4 Alpha 3 Plus 1 Gained 1 Lost 1 None Beta 4 Minus 2 Lost 2 Lost 2 Minus 4 Alpha 5 Plus 1 Gained 1 Lost 1 None Beta

Answer the following questions: 1. What changes take place in the nucleus when an alpha particle is emitted (released)?

Lose 2 protons and 2 neutrons

2. What element or subatomic particle is an "Alpha Particle"? Helium-4

3. What changes take place in the nucleus when a beta particle is emitted? Lose 1 neutron, gain a proton (neutron BECAME a proton)

4. What element or subatomic particle is a "Beta Particle"? An electron

5. When an alpha particle is lost from an atom, where on the periodic table would you look to find the product? To the left or right of the initial atom? Two to the left of the initial Atom

6. Fill in the missing parts of the nuclear reactions below: a. Bottom: 19, ?: K b. Top: 230, Bottom: 90, ?: Th c. Top: 35, Bottom: 15, ?: P d. Top: 234, Bottom: 90, ?: Th 4 e. ?: Alpha ( 2He) f. ?: Beta (e-1)

7. Does the identity of the atom change during radioactive decay? Why or why not? Yes because the number of protons (atomic number) is different

8. If an atom of element number 85, astatine, undergoes alpha decay, what atom will be produced? Bismuth

9. If an atom of element number 87, francium, undergoes beta decay, what atom will be produced? Radium

10. Which isotopes are most likely to decay? Radioactive/Unstable isotopes

Chem A Unit ANSWER KEYS (not for students) Page 96 4.8a Half Life Lab Tuesday, March 17, 2020 11:31 AM Purpose: Simulate the transformation of a radioactive isotope over time Graph the data to define half-life.

Background: Unstable isotopes become more stable atoms. To do this, they undergo radioactive decay. Each atom has a different rate of radioactive decay that can occur. During this simulation we will discover about how much of each atom undergoes decay each time the reaction happens.

Materials: Container of 100 coins (representing the radioactive isotope) – Tailium (T) graph paper paper clips (representing the new stable atom) – Paperclipium (Pp)

Pre-Laboratory Questions:

1. What is an isotope? Give one example. Elements with the same name, but different number of neutrons (mass numbers): Helium-3, Helium-4

2. What causes an atom to undergo radioactive decay? It is unstable/radioactive

If you have physical supplies (100 pennies and paper clips) If you don't! Procedure: Procedure:

1. Put the paperclips to the side. These are the stable atom 1. Go to https://www.random.org/coins/ Paperclipium (Pp) 2. Set the coin number to 100 and select any coin (preferrably 2. Turn all the coins to tails and count the total number of the coins. one with obvious heads/tails) Record in data table at time zero. 3. These are all radioactive (unstable) atoms called Tailium (T) 3. Put all the coins in the cup. These are all radioactive (unstable) 4. Select "Flip Coins" atoms called Tailium (T) 5. Count all the coins that are heads up 4. Shake all the coins gently. 6. These are all the coins that have now decayed and become 5. After 30 seconds pour the sample out onto the lab table. This Paperclipium represents 1 year. 7. Record how many Tailium are remaining after 1 year. Record 6. Separate the sample into heads and tails and count the tails – these how many Paperclipium there are now. are still Tailium. Record the numbers in data table. Place ONLY 8. The remaining coins need to be flipped again – go back to the these back into the container. previous screen. 7. Any coin that is heads up is now Paperclipium, so put them to the 9. Set the number of coins to flip as the number of Tailium you side and replace them with paperclips. had remaining. (for example, if 47 coins were heads, 100-47= 8. Add the paper clips to the container to bring the number of objects 53. You would set the number to 53) back to the starting number (the total number of atoms should NOT 10. Repeat steps 2-9 until there are zero Tailium Remaining. change). Shake gently. 11. Complete the calculations on the data table for individual and 9. Repeat steps 4 through 8 until no Tailium is left (all coins are class results. paperclips). 12. Graph the amount of Tailium left after each half life on the 10. Complete the calculations on the data table for individual and class graph for your data and the class data. results. 11. Graph the amount of Tailium left after each half life on the graph for your data and the class data.

Remember that Tallium doesn't just disappear. It becomes a new element through decay (Paperclipium)

Data Table:

Chem A Unit ANSWER KEYS (not for students) Page 97 Data Table:

Trial # Years Tailium Paperclipium % Tailium remaining Individual

0 0 0 100% Data should be close to a 50% drop 1 1 every time as pennies have a 50% 2 chance of being heads or tails 3 4 5 6 7 8 9 10

3. Half-Life: How many years did it take Tailium to only have 50% remaining? About 1 year

Graph your data:

Below is a graph of class data collected last year.

Chem A Unit ANSWER KEYS (not for students) Page 98 Analysis:

1. How did your data compare to the class data?

Various Answers

2. What did the pennies that landed as tails represent?

Atoms that did not decay and remained Tailium

3. Why were the pennies that landed as heads removed and replaced by paperclips?

They had gone through alpha or beta decay and were now new, more stable elements

4. At what point on the graph is there only half of the Tailium remaining? Where did it go?

After 1 year. It was now a new element - paperclipium

5. How long did it take for Tailium to go from 50% remaining to 25% remaining? 1 year again

6. 25% is HALF of 50%. What do you notice about the time it took for 50% of Tailium to change compared to how long it took for Tailium to lose half again (50%-25%). 1 year again

7. How long did it take for Tailium to go from 25% remaining to 12.5% remaining? 1 year again

8. Did the amount of time it take for Tailium to decay by 50% change or stay the same? Stayed the same

Conclusion:

9. Use questions 4-5 to select the correct definition of “half-life”? a. When there is only half of the element remaining b. The amount of time it takes for half of a sample to decay into a new element c. The amount of time it takes for half of a sample to disappear d. The amoutn of time it takes for a sample to completely decay into a new element

Chem A Unit ANSWER KEYS (not for students) Page 99 d. The amoutn of time it takes for a sample to completely decay into a new element

10. Explain your answer to 9. It is a measurement of time and it was how long it took tailium to become half

11. Is half-life a measurement of time or amount? Explain your answer.

Time because the amount was different each time

Three Students analyze the data on the graph below based on this lab: Time (days) Amount of Substance A (g) Amount of Substance B (g) Percent of A remaining 0 1000 0 100 1 700 300 70 2 500 500 50 3 350 650 35 4 250 750 25 5 175 825 17.5 6 125 875 12.5 7 87.5 912.5 8.75 8 62.5 937.5 6.25

Student A: The half-life of Substance A must be 1 day because that is when data was recorded. Student B: I disagree, the half-life must be 2 days because that is when 50% of Substance A is now Substance B. Student C: I think the half-life is 500g because that is half of what Substance A started with.

12. Which student do you agree with and why? Student B because A is not looking at amounts and C is not looking at time

13. Confirm your ideas by watching the video at the very bottom of this page. Note: do not worry too much about the math!

Exponential Decay: Penny Experiment

GCSE Physics - Radioactive Decay and Half Life #35

Chem A Unit ANSWER KEYS (not for students) Page 100 Chem A Unit ANSWER KEYS (not for students) Page 101 4.8b Half Life Notes and Problems Tuesday, March 17, 2020 11:31 AM To fill in the notes, be sure to watch the video at the very bottom of the page on 4.8a. 1. Half-life: The time it takes for the amount of a radioactive isotope to decrease by HALF . This varies considerably between different atoms. 14 a. Half-life of C = 5,730 years 238 b. Half-life of U = 4.5 billion years 2. After an atom goes through decay, it doesn’t just disappear. This means when half the Carbon-14 atoms have gone through beta decay, they’re not gone – they are now a new more stable element. Hint: look back at your equations for beta decay (4.7b) to figure out the new element. Answer these questions using the graph below:

3. The number of grams present in the original sample of sodium-24 is 400g. (don’t forget units!) 4. The half-life of sodium-24 is 15 hrs. (don’t forget units!) 5. After 30 hours, 100g (25%) of sodium-24 are present. 6. After 45 hours, about 50g (12.5%) is present. 7. If the sample has 125 g of sodium-24 left, then 25hrs has passed.

Chem A Unit ANSWER KEYS (not for students) Page 102 Half Life Practice Note: Half-life is the amount of time it takes for half of the mass of an unstable atom to decay. Directions: These problems are both practice with half-life and giving some costs/benefits of using radioactivity. Be sure you are paying attention to the uses of half-life as well as how to calculate it.

1. Iodine-131 is used to destroy thyroid tissue in the treatment of an overactive thyroid. The half-life of iodine-131 is 8 days. If a hospital receives a shipment of 200 g of Iodine 131, how much I-131 would remain after 32 days? Trials Half-life (t) Mass Percent To figure out percent (this works for grades too!): Mass Remaining ÷ Total Mass x 100 0 0 200g 100% 1 8 days 100g 50% 2 16 days 50g 25% 3 24 days 25g 12.5% 4 32 days 12.5g 6.25%

2. Iodine primarily goes through Beta Decay when it decays. What element is 50% of the Iodine-131 atoms after 8 days? Xenon -131

3. Technetium-99 is used for brain scans. If a laboratory receives 200g of this isotope and after 24 hours only 12.5 g of this isotope remain, what is the half-life of technetium-99? Trials Half-life (t) Mass Percent 0 0 200g 100% NOTE: they will try to put the 1 6hrs 100g 50% time as exponentially increasing 2 12hrs 50g 25% as well. This is the most common 3 18hrs 25g 12.5% mistake. Incorrect example: 3, 6, 12 4 24 hours 12.5g 6.25%

4. Technetium-99 primarily releases gamma radiation as it decays. This means that after 24 hours, 187.5 grams the atoms of Technetium-99 are still Technetium-99, but not giving off gamma radiation.

5. Mercury-197 is used for kidney scans and has a half-life of 3 days. If the amount of mercury-197 needed for a study is 1.0 gram and the shipment time is 15 days, what is the minimum mass of mercury-197 that needs to be ordered? Trials Half-life (t) Mass Percent 0 0 32g 100% 1 3 days 16g 50% 2 6 days 8 g 25% 3 9 days 4 g 12.5% 4 12 days 2 g 6.25% 5 15 days 1.0g 3.125%

6. Mercury-197 goes through a different kind of beta decay where a proton becomes a neutron. This means that after 15 days, most of the atoms in the sample would be Gold-197.

7. The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g? Trials Half-life (t) Mass Percent 0 0 4.0g 100% 1 25 years 2.0g 50%

Chem A Unit ANSWER KEYS (not for students) Page 103 2 50 yrs 1.0g 25% 3 75 yrs 0.5g 12.5% 4 100 yrs 0.25g 6.25%

8. Strontium-90 goes through beta decay. This means that after 100 years, most of the sample will now be Yttrium-90.

9. The isotope H-3 has a half life of 12.26 years. Find the percent remaining after approximately 49 years. Trials Half-life (t) Percent 0 0 100% 1 12.26 years 50% 2 24.52 years 25% 3 36.78 yrs 12.5% 4 49.04 yrs 6.25% 5 61.3 yrs 3.125%

10. Hydrogen-3 also goes through beta decay. This means it becomes Helium-3 when it decays.

11. How long will it take for 64.0g of Rn-222 (half-life = 3.8235 days) to decay to 8.00g? Trials Half-life (t) Mass Percent 0 0 64.0g 100% 1 3.8235 days 32g 50% 2 7.647 days 16g 25% 3 11.4705 days 8g 12.5% 4 15.294 days 4g 6.25% 5 19.1175 days 2g 3.125%

12. Radon-222 goes through alpha decay. This means that the “missing” 56g has actually become Polonium-218.

13. Silicon-31 has a half-life of approximately 2.5 hours. If we begin with a sample containing 1000 mg of Si-31, what is the approximate amount remaining after 10 hours? Trials Half-life (t) Mass Percent 0 0 1000mg 100% 1 2.5 hours 500mg 50% 2 5 hrs 250mg 25% 3 7.5hrs 125mg 12.5% 4 10hrs 62.5mg 6.25%

14. Silicon-31 goes through beta decay to become Phosphorus-31 as it decays.

15. Cesium-137 was the long lived isotope released during the Chernobyl explosion in Russia that killed 60 people immediately, and potentially another 4000 due to radiation. Cesium has a half-life of 30 years and the reactor released 80,000 KBq. Chernobyl will only be safe to live in again if the levels are less than 1000KBq (less than 1.25% of original amount). Trials Half-life (t) Mass Percent 0 0 80,000 KBq 100% 1 30 years 40,000 KBq 50% 2 60 yrs 20,000 KBq 25%

Chem A Unit ANSWER KEYS (not for students) Page 104 3 90 yrs 10,000 KBq 12.5% 4 120 yrs 5,000 KBq 6.25% 5 150 yrs 2,500 KBq 3.125% 6 180 yrs 1,250 KBq 1.563%

16. How long until Chernobyl is livable again (be sure to read question 15 closely)? Over 180 years

17. Cesium-137 also goes through beta decay. This means after one half life, 50% of the cesium will now be Barium-137.

Chem A Unit ANSWER KEYS (not for students) Page 105 SIR PART 3: Types of Decay and Half-Life Monday, March 23, 2020 11:27 AM

Chem A Unit ANSWER KEYS (not for students) Page 106 Chem A Unit ANSWER KEYS (not for students) Page 107 Chem A Unit ANSWER KEYS (not for students) Page 108 Chem A Unit ANSWER KEYS (not for students) Page 109 Chem A Unit ANSWER KEYS (not for students) Page 110 Answer the questions below:

Chem A Unit ANSWER KEYS (not for students) Page 111 1. If I wanted to create thorium-200, would you expect that element to be stable? Why or why not? No. It is below the band of stability therefore it was break apart rapidly. It does not have enough neutrons to be stable.

2. Why would gamma radiation be considered more dangerous than alpha or beta radiation? Gamma radiation can travel through more. It is so small/fast that only lead will block it.

3. Complete the following nuclear equations:

a.

233 A. 91Pa 6 B. 3Li b. 32 C. 16s

c.

4. Complete the following half-life questions. A. Os-182 has a half-life of 21.5 hours. Fill out the following table to figure out how much Os-182 I started with to end up with 10 g after 107.5 hours. Mass ½-life Time 320g 0 0 160g 1 21.5 80g 2 43 40g 3 64.5 20g 4 86 10g 5 107.5

B. The half-life of Zn-71 is 2.4 minutes. If I start with 100g, how much is left after 7.2 minutes? Show your work.

1/2 Life Time 0 0 1 2.4 2 4.8 3 7.2

So n=3 because of the table above Plug into equation:

Chem A Unit ANSWER KEYS (not for students) Page 112 Plug into equation:

= 12.5

Answer: 12.5g

Chem A Unit ANSWER KEYS (not for students) Page 113 Learning Tracking Tool Tuesday, March 17, 2020 11:31 AM Has the pursuit of Nuclear Science benefited or harmed society?

Lesson What did we figure out? Drawing simple models of nuclear change. How does this add to our argument How does this add to our Self-Assess: What questions do I Summarize key information and For each reaction, try to draw a simple diagram of of the COSTS of nuclear sciences? argument of the BENEFITS of Where am I with my have? activities with a description and/or the change Identify any con arguments you nuclear sciences? understanding of the What additional picture. discovered from this activity. Identify any pros arguments you phenomenon? information do you discovered from this activity. (Example: Ready to debate need to understand both sides using scientific the phenomenon? reasoning, starting to get it, need more information) 4.1 Nuclear Phenomenon We watched a video about the nuclear NO DRAWING NEEDED Nuclear science has hazardous waste Various answers from nei.org bombings in Japan and read some and was used to create bombs possible uses of nuclear sciences. No additional information needed. 4.2 Isotopes - How is the The mass on the periodic table is a NO DRAWING NEEDED NO ARTICLES FOR THIS ACTIVITY NO ARTICLES FOR THIS ACTIVITY atomic mass calculated? decimal because...it is the average of all the isotopes of each element 4.3 Band of Stability - What If elements are outside the band of NO DRAWING NEEDED Radioactive Iodine causes cancer Radioactive isotopes can be used types of isotopes exist in stability because of an imbalance of for cancer treatment nature? protons and neutrons, it will...decay and change to a different element 4.4 Fission Phet - How is the Fission is...the splitting of an unstable Draw fission: Fission releases a massive amount of Fission Nuclear reactors create a atomic number and mass atom energy that has been used in massive amount of energy affected by fission? How is weapons and waste that is difficult to compared to coal and don't energy related? The atomic mass will...decrease clean up release greenhouse gasses

The atomic number will...decrease

The number of atoms coming out of the reaction is (greater/less) than the number of atoms that went into the reaction. 4.5 Fusion Activity - How is Fusion is...the combining of atoms Draw fusion: Adding fusion to nuclear weapons Fusion is natural and occurs in the atomic number and increases their power by a lot stars. It also has the potential to mass affected by fusion? The atomic mass will...increase create everlasting energy in power plants if it can be The atomic number will...increase harnessed

The number of atoms coming out of the reaction is (greater/less) than the number of atoms that went into the reaction.

4.6 Cloud Chamber Lab - Nuclear change is (common/uncommon) NO DRAWING NEEDED NO ARTICLES FOR THIS ACTIVITY Radioactive decay is naturally What evidence led to and there (is/is not) evidence of decay. occurring different forms of nuclear decay? 4.7 Alpha and Beta Decay - Alpha decay is...when a radioactive Draw Alpha Decay: Particles released from decay are Alpha decay is used in smoke How can we model alpha element loses a helium atom (2p/2n) dangerous and can pass through detectors to save lives and beta decay? How do and becomes a new, more stable materials they change the atom? element

The atomic mass will...decrease by 4

The atomic number will...decrease by 2

The particle that is ejected is...helium-4 Draw Beta Decay:

Beta decay is...when a radioactive element ejects an electron causing a neutron to become a positive proton (there is also positive beta decay, but students don't need to know this)

The atomic mass will...stay the same

The atomic number will...increase by 1

The particle that is ejected is...an electron (and neutrino, but students don't need to know this)

4.8 Half Life - At what rate Half-life is defined as...the amount of NO DRAWING NEEDED Chernobyl being inhabitable because Decay of controlled substances do atoms decay? How can time it takes for half of a sample of of long half-life of radioactive used for medical procedures and we use that information? radioactive material to decay to a new, substances treatment more stable element

When an element is decaying, it is (disappearing/not disappearing). It is...becoming a new, more stable element

Chem A Unit ANSWER KEYS (not for students) Page 114 Isotopes of Elements Chart (Band of Stability) Wednesday, January 15, 2020 8:08 AM

Reading the Isotopes Graph: 1. Start by finding the atomic number of the element on the X axis. 2. From that atomic number, go up until you see the boxes that are lined up with that number 3. Look at where they line up with the number of neutrons (notice it is NOT the mass – you have to calculate that yourself) to figure out which isotopes exist 4. Thinking about the colors: a. If the box is BLACK, it is the most common b. If the box is GRAY, it is common but not the most c. If the box is WHITE, it is radioactive and will naturally decay d. If there is no box, it is not an element that exists in nature. This means that it would be so radioactive that it would immediately decay.

Chemistry Resources Page 115 Chemistry Resources Page 116 Periodic Table - Colored Wednesday, January 15, 2020 8:10 AM

Chemistry Resources Page 117 Periodic Table with Names (not colored) Wednesday, January 15, 2020 8:16 AM

Chemistry Resources Page 118