Name:______Campus: CHS Teacher:______
Corsicana Independent School District Chemistry May 4 – May 8
Student Directions 1. Read and study the Nuclear Chemistry Notes (KEEP) 2. Read and study the “Radium Girls: The dark side of luminous watches” (KEEP) 3. Use the information from the notes and article to take the quiz (RETURN)
Unstable Nuclei and Radioactive Decay Nuclear Chemistry Radioactivity Chemical reactions involve only •Chapter 4 & electrons, NOT the nucleus. 25 Nuclear Chemistry Protons determine the identity of an atom. Change the protons, it is a different atom!!
Unstable Nuclei and Radioactive Decay
Nuclear Radioactivity Reactions- - substances reactions spontaneously which involve emit radiation a change in an atom’s nucleus
Radioactive atoms Emit radiation because their
Radiation- rays and nuclei are unstable. particles emitted by Radioactive decay- a process the radioactive in which unstable radioactive material atoms lose energy by emitting By emitting radiation radiation, atoms of one element can change into atoms of another element.
1 Unstable radioactive atoms 3 Types of Radiation undergo radioactive decay until they form stable 1800’s Scientists directed non radioactive atoms of a radiation between 2 electrically charged plates and different element. found there were 3 different types; some deflected to the negative, some to the positive, and some were not deflected at all.
Alpha, Beta, and Gamma Alpha Radiation
an alpha particle (we use the symbol α) Alpha radiation - is positive attracted to a beta particle (symbol β) is negative negative plate a gamma ray (symbol γ) is neutral and made of alpha particles and gives off gamma rays.
Alpha Radiation Alpha particle Decreases the mass number Alpha Particle- by 4, and the atomic 2 protons, and 2 number by 2. neutrons so it is positive +2 and mass of 4. Equal to a Helium-4 nucleus.
2 Example
Radium decays into Radon by nuclear equation -show emitting an alpha particle the atomic number and the mass number
Note the equation is balanced
Beta Radiation Beta Particles A neutron becomes a proton and an electron. Beta radiaton - attracted to the The electron leaves the atom at high speed. positive plate, made of beta particles and gives off gamma rays.
beta particles –made of an electron with a negative charge -1.
The new proton stays in the nucleus increasing the atomic number by 1. H becomes He! Beta particle Mass number stays the same. increases the atomic number by one
Carbon-14 becomes Nitrogen by emitting a beta particle.
3 Gamma Radiation – made of gamma rays Nuclear Stability Gamma Rays- high-energy radiation that possesses no mass and no charge but releases the most energy. The ratio of neutrons to protons determines an atom’s stability. atoms with too many or too few neutrons are unstable. They go through radioactive decay to form a nucleus with a stable composition of neutrons and protons making a stable nonradioactive atom.
Nuclear Chemistry Nuclear Radiation
1895- William Roentgen found that invisible rays were emitted when electrons He took “pictures” of bombarded the surface of his wife’s hand. certain materials. X-rays caused Discovered X-rays. photographic plates to darken In 1901 Röntgen was awarded the very first Nobel Prize in Physics.
Henri Becquerel
1896 - studied minerals that emit light
after being exposed to Accidentally, he discovered uranium sunlight- called emitted radiation without an external phosphorescence. source of energy such as the sun. He wondered if they Becquerel had discovered radioactivity, the spontaneous emission of radiation by also emitted X-rays. a material.
4 The Curies
Later, Becquerel demonstrated that the radiation shared certain characteristics 1898 - Marie with X rays but, unlike X rays, radiation could be deflected by a magnetic field and and Pierre therefore must consist of charged Curie –isolated particles. the elements that were emitting the rays.
polonium,
and radium Rate of radioactive emission of charged particles from elements could be measured and compared. In addition, she found that there was a decrease in the rate of radioactive emissions over time and that this decrease could be calculated and predicted. But perhaps Marie Curie's greatest and most unique achievement was her realization that radiation is an atomic property of matter.
Nobel Prize in Physics 1903 – was shared; Curies and Becquerel for work Types of Radiation in radioactivity Nobel Prize in Chemistry 1911 – Marie Radioisotopes- Curie for her work with the elements isotopes of atoms Polonium and Radium. with unstable nuclei C-14 is a radioisotope of C-12
5 Most common types of radiation are X-Rays alpha, beta, and gamma rays
X-rays and gamma rays – high-energy electromagnetic radiation that is extremely penetrating and damaging to living tissue. Blocked by lead and concrete.
Transmutation
Transmutation – the conversion of an atom of one element to an atom of another element.
Can be natural or induced
All elements with atomic numbers 93 and greater are transuranium.
Transuranium elements – produced in the laboratory by induced transmutation and are radioactive. Made by particle accelerators (synchrotrons) bombarding the nucleus with high-energy alpha, beta, or gamma radiation.
6 Radioactive Decay Rates
Half-Life- time required for For example: Strontium-90 one-half of a radioisotope’s has a half life of 29 years. nuclei to decay into its If you had 10 grams today, then 29 years from now products you would have 5 grams left. The other 5 grams would have transmutated into the stable element.
If the half-life of iodine-131 is 8.04 days, how much of a 100 gram sample will Radiochemical Dating remain after 8.04 days?16.08 days? 32.16 days? The half-life of any radioisotope is constant Half life Time in Grams Radiochemical dating – process days of determining the age of an object 0 0 100g by measuring the amount of a 1 8.04 50g certain radioisotope remaining in that object. 2 16.08 25g 3 24.12 12.5g 4 32.16 6.25g
The carbon-14 decays with its half- life of 5,700 years, while the amount of carbon-12 remains constant in the sample. By looking at the ratio of carbon-12 to carbon- 14 in the sample and comparing it to the ratio in a living organism, it is possible to determine the age of a formerly living thing fairly precisely. Because the half-life of carbon-14 is 5,700 years, it is only reliable for dating objects up to about 60,000 years old. However
7 Half Percent of Carbon-14 left to Percent Lives of Carbon-12 of a living sample.
0 100% C- 14
1 50% 50% C-12 C-14
2 25% 75% C-12 C-14
3 87.5% C-12
Fission and Fusion of Atomic Nuclei
Other useful radioisotopes for radioactive dating include: Uranium -235 (half-life = 704 million yrs) Nuclear Fission- the splitting of a Uranium -238 (half-life = 4.5 billion yrs) nucleus into Thorium-232 (half-life = 14 billion yrs) fragments; Rubidium-87 (half-life = 49 billion yrs). accompanied by a very large release of energy
The neutrons released can cause more fissions, which releases more Chain reaction –self- neutrons causing more fissions and sustaining process in which one so on. reaction initiates the next.
Critical mass – a sample that is massive enough to sustain a chain reaction.
More than a critical mass can generate a nuclear explosion.
8 Nuclear Reactors
4. A coolant, like water is used to 1. Fission is used to generate power in cool & carry off heat caused by nuclear power plants reaction 2. Fuel rods made of enriched Uranium 5. The water generates steam, emit neutrons to sustain a chain reaction which powers turbines, which produce electricity. 3. Control rods absorb the neutrons and sustain the chain reaction while preventing it from racing out of control
Concerns
Radioactive materials have long half-lives and continue to be damaging for many years. Overexposure can cause cancer or even death.
Nuclear Fusion- the combining No good way to dispose of nuclear of atomic nuclei; capable of waste because it can contaminate water, soil, and air releasing large amounts of energy
9 Hydrogen Fusion
Four atoms of H fuse to form He Ex: Sun 4 H 1He + ENERGY powered by a series of Each H atom’s mass = 1.0081 amu fusion reactions 4 x 1.0081 = 4.0324 amu high amount of energy is Each He atom’s mass = 4.0039 required to create reaction
One Helium atom weighs .0285 amu less than 4 H atoms. Mass of reactants must = mass of products according to the Law of Conservation of Mass, Matter cannot be created or destroyed 4 H 1He + ENERGY 4.0324 4.0039 + .0285 Does mass or matter disappear?
The .0285 amu is the matter that So what happened to it? changes to ENERGY which is multiplied trillions of times to give our sun its heat and light.
Thermonuclear Fusion occurs reaction- another in stars, name for fusion which derive reaction their energy The heat required for from fusion only occurs in hydrogen an atomic explosion and helium. or in the plasma state.
10 Applications and Effects of Nuclear Fusion is difficult to achieve in a Reactions lab because of the very strong repulsion of nuclei. Ionizing radiation - radiation Controlled fusion is achieved in particle accelerators to produce energetic enough to ionize many synthetic elements. (damage) matter with which it collides. Detected by Geiger counters
Uses of Radiation
Radiotracer - radioisotope that emits non-ionizing radiation and is used to signal the presence of an element or specific substance. a. analyze reactions b. detect diseases c. PET scans
Medical Uses of Radiation PET scan Diagnostic: Radiotracers such as technitium-99 can be injected in the blood stream and then tracked through the body to see if organs are functioning properly; also can help diagnose cancer (PET scan)
11 Commercial applications
Smoke detectors: have a tiny mass of Therapy: Radiation americium-241, which is a source of treatments can kill the alpha radiation cancer cells in cancer
patients Rifle sights: tritium is used with phosphor to increase nighttime firing accuracy
Exit signs: luminescence is due to a small amount of radioactivity
Food irradiation: exposing food to ionizing radiation to destroy microorganisms, bacteria, viruses, and insects
Biological effects
gamma rays are particularly harmful because they easily penetrate and damage human tissue skin usually stops alpha beta only penetrates 1-2 cm
12 Radium Girls: The dark times of luminous watches
Written by Jacopo Prisco, CNN A century ago, glow-in-the-dark watches were an irresistible novelty. The dials, covered in a special luminous paint, shone all the time and didn't require charging in sunlight. It looked like magic. One of the first factories to produce these watches opened in New Jersey in 1916. It hired about 70 women, the first of thousands to be employed in many such factories in the United States. It was a well-paid, glamorous job. For the delicate task of applying the paint to the tiny dials, the women were instructed to point the brushes with their lips. But the paint made the watches glow because it contained radium, a radioactive element discovered less than 20 years earlier, its properties not yet fully understood. The women were ingesting it with nearly every brushstroke. They became known as the "Radium Girls." A miracle cure Radium was discovered by Nobel laureate Marie Curie and her husband Pierre in 1898. It was quickly put to use as a cancer treatment.
"Because it was successful, it somehow became an all-powerful health tonic, taken in the same way as we take vitamins today -- people were fascinated with its power," said Kate Moore, author of "The Radium Girls," in a phone interview. It was a proper craze. Radium became an additive in a number of everyday products, from toothpaste to cosmetics and even food and drinks. One such preparation, called Radithor, was simply distilled water with tiny amounts of the substance dissolved in it. Boldly advertised as "A Cure for the Living Dead" and "Perpetual Sunshine," it promised to tackle various ailments from arthritis to gout.
A bottle of Radithor. Credit: John B. Carnett/Bonnier Corp. via Getty Images
"People knew that radioactivity released energy. And they didn't see how adding some energy to their bodies could possibly be harmful, said Timothy Jorgensen, a radiation expert at Georgetown University and author of "Strange Glow: The Story of Radiation." "Radium products were used for any ailment where lack of energy was seen to be the root cause -- from common fatigue to impotence," Jorgensen said in an email. Far from being a panacea, radium was deadly. One user, American socialite and athlete Eben Byers, became notorious for drinking a bottle of Radithor every day for years -- and then dying from it in 1932. The headline of a Wall Street Journal story about his death reads, "The radium water worked fine until his jaw came off."
A slow killer When ingested, radium is particularly dangerous: "Chemically, it behaves very much like calcium," said Jorgensen. "Since the body uses calcium to make bone, ingested radium is mistaken for calcium and gets incorporated into bone. So the major health risk of ingesting radium is radiation-induced bone necrosis and bone cancers. How soon they develop depends upon the dose, but at the very high doses that the Radium Girls were exposed to, just a few years." The luminous paint, which worked by converting the radiation into light through a fluorescent chemical, was one of the most successful radium-based products. By putting the brushes in their mouths, the Radium Girls were especially at risk -- so why did they do it? "Because it was the easiest way to get a fine point on the brush, to paint on numbers as small as a single millimeter in width," said Moore.
A 1921 advertisement for Undark, a luminous radium paint. Credit: Public Domain
But the girls didn't embrace this technique blindly. "The first thing they asked was (whether) the paint was harmful, but the managers said it was safe, which was the obvious answer for a manager of a company whose very existence depended on radium paint." Not all that glitters When the luminous watches grew fashionable in the early 1920s, the world was already becoming aware of the risks of radioactivity. But radiation poisoning isn't immediate, so years went by before any of the workers developed symptoms. "It's mind-boggling to think about what was known," said Moore. "We knew from the turn of the century that radium was dangerous and large amounts of it could destroy human tissue. But one of the tricky things with it is that it does give this illusion of good health, because it stimulates the red blood cells, although obviously in the long term you're poisoning yourself."
A 1924 ad for a radium hair treatment. Credit: H.W. Cherry/Library of Congress
The Radium Girls actually believed they were getting healthier by working with the new wonder drug -- the most expensive substance in the world at the time, costing the equivalent of $2.2 million per gram in today's money. Adding to the allure of the job, the girls were listed as 'artists' in their town directories. Since it was all so attractive, they even encouraged their sisters and friends to join them. One sinister side effect was that the shimmering radioactive dust would fill the air when the paint was mixed, ending up on the women's hair and clothes." And the girls at the time obviously loved it and talked about wearing their good dresses to the plant, so that when they'd go out in speakeasies later they would be the ones shimmering and shining." Radium jaw In the early 1920s, some of the Radium Girls started developing symptoms like fatigue and toothaches. The first death occurred in 1922, when 22-year-old Mollie Maggia died after reportedly enduring a year of pain. Although her death certificate erroneously stated that she died of syphilis, she was actually suffering from a condition called "radium jaw." Her entire lower jawbone had become so brittle that her doctor removed it by simply lifting it out. "The radium was destroying the bone and literally drilling holes in the women's jaws while they were still alive," said Moore. Yet it would take another two years before the company that owned the factory, the United States Radium Corporation, took any action at all, through an independent investigation commissioned mostly to investigate the declining business rather than the health of the workers.
Radium Girls work in a factory of the United States Radium Corporation. Credit: Public Domain
In 1925 Grace Fryer, one of the workers from the original New Jersey plant, decided to sue, but she would spend two years searching for a lawyer willing to help her. She finally filed her case in 1927 along with four fellow workers, and made front-page news around the world. The case, settled in the women's favor in 1928, became a milestone of occupational hazard law. By this time, the dangers of radium were in full view, the lip-pointing technique was discontinued and the workers were being given protective gear. More women sued, and the radium companies appealed several times, but in 1939 the Supreme Court rejected the last appeal. The survivors received compensation, and death certificates would start reporting the correct cause of death. The year before, the Food and Drug Administration banned the deceptive packaging of radium- based products. Radium paint itself was eventually phased out and has not been used in watches since 1968. An enduring legacy
It's hard to calculate how many women suffered health problems due to the ingestion of radium, but they certainly number in the thousands, according to Moore. Some of the effects would only be felt much later in life through various forms of cancer. With a half-life of 1,600 years, once the radium was inside the women's bodies, it was there for good. The legacy of the Radium Girls lives on through the ripples that their deaths created in labor law and our scientific understanding of the effects of radioactivity. "In the 1950s, during the Cold War, many agreed voluntarily to be studied by scientists, even with intrusive examinations because they had been exposed for prolonged periods of time," said Moore. "Almost everything we know about radiation inside the human body, we owe to them," she said.
Source:
Prisco, Jacopo. “Radium Girls: The dark times of luminous watches.”CNN Style, Turner Broadcasting System Inc., 19 December 2017, https://www.cnn.com/style/article/radium‐girls‐radioactive‐paint/index.html.
Name: ______CHS Teacher: ______(RETURN THIS PAGE) Nuclear Chemistry Quiz
1. Which particle has the greatest mass? a. Alpha b. Beta c. Gamma d. Positron
2. In the nuclear equation given below, calculate the mass number of the alpha particle.
a. 0 b. 4 c. 234 d. 238
3. The greatest downside to a nuclear powerplant is: a. Water is needed for coolant b. They produce wastes that remain radioactive for thousands of years c. The enormous cost of building a power plant d. Interruption of power
4. What particles form the nucleus of an atom? a. Protons and neutrons b. Protons and electrons c. Electrons only d. Electrons and Neutrons
5. How does the nucleus of an atom change after a gamma irradiation? a. The atomic mass reduces by four and the atomic number reduces by two. b. The atomic mass remains the same, but the atomic number increases by one. c. The atomic mass remains the same, but energy is lost as the nucleus decays. d. The atomic mass changes by one, but the atomic number remains the same.
6. Beta particles are made of ______. a. Helium nuclei b. Neutrons c. Electromagnetic waves d. Electron
Name: ______CHS Teacher: ______(RETURN THIS PAGE)
7. When hydrogen nuclei combine to form a helium atom, this is called ______. a. Fusion b. Fission c. Radioactivity d. Mutation
8. The rays and particles emitted by radioactive material is called ______. a. Fission b. Nuclear equation c. Protons d. Radiation
9. What is the charge on an alpha particle? a. 2+ b. 1+ c. 1‐ d. 2‐
10. What is the change in atomic number when an atom emits gamma radiation? a. Decreases by 2 b. Decreases by 1 c. Remains the same d. Increases by 1
11. How many neutrons are there in an alpha particle? a. 0 b. 1 c. 2 d. 3
12. The type of nuclear process most commonly used in nuclear power plants is _____. a. Fission b. Fusion c. Radioactivity d. Mutation
13. Which of the following is a symbol for the beta particle? a. α b. β c. γ Name: ______CHS Teacher: ______(RETURN THIS PAGE)
14. Which particle has no charge and no mass? a. Alpha b. Beta c. Gamma d. Positron
15 – 20:
Using the answer choices given, match each of the following with their correct answer from the Radium girls article. You will only use an answer once.
Answer Choices: 15. Scientist that Marie Curie • The United States Radium Corporation founded the Eben Byers • Grace Fryer element Radium
Mollie Maggia • Clock painters Food and Drug Administration • Cracked/Falling out teeth
Answer:______
16. Group to ban deceptive packaging of Radium products Answer:______
17. Radium girls job that caused them to ingest the Radium Answer:______
18. Symptom of ingested Radium Answer:______
19. Who was the American who drank one Radithor a day? Answer:______
20. First Radium girl to die Answer:______