Section 4.1 Defining the Atom (Pg.101-103)
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Chapter 4: Atomic Structure
Section 4.1 Defining the Atom (pg.101-103) 1. Distinguish between the atomic theories proposed by Democritus and Dalton. 2. Be familiar with the individual components of Dalton’s atomic theory
Section 4.2 Structure of the Nuclear Atom (pg. 104-108) 1. Describe the characteristics of sub atomic particles including relative mass and charge. 2. Explain Thomson’s discovery of the electron using a cathode ray tube. 3. Describe Thomson’s proposed model of the atom. 4. Explain Rutherford’s gold foil experiment and its results. 5. Describe Rutherford’s nuclear model of the atom.
Section 4.3 Distinguishing Among Atoms (pg. 110-119) 1. Determine the number of protons and electrons in any element. 2. Define an atomic mass unit 3. Determine the number of neutrons in an atom given its mass number and vice versa. 4. Determine the atomic mass of an element from isotopic data 5. Define mass defect and binding energy (not in book, see supplemental problem #2) 6. Describe the organization of the periodic table in terms of periods and groups 7. Identity an element by its period and group numbers
Chapter 25: Nuclear Chemistry
Section 25.1 Nuclear Radiation (pg.799-802) 1. Distinguish between the three main types of nuclear radiation in terms of their composition, charge, mass and their relative values of shielding, energy, biological hazard and actual hazard.
Section 25.2 Nuclear Transformations (pg. 803-808) 1. Distinguish between nuclear force and electrostatic force in the nucleus of an atom. 2. Explain a nuclides stability in terms of its neutron to proton ratio as it relates to the band of stability. 3. Determine what type of decay a nuclide will undergo based on its neutron to proton ratio. 4. Write nuclear decay reactions for alpha decay, beta decay, positron emission and electron capture. 5. Define half-life 6. Calculate the initial amount, final amount, half-life, time elapse, or the number of half-lives for a given radioactive isotope. 7. Explain the use of carbon dating in determining the age of a fossil. 8. Distinguish between transmutation and induced transmutation reactions. 9. Write equations for induced transmutation reactions.
Section 25.3 Fission and Fusion of Atomic Nuclei (pg. 809-813) 1. Distinguish between nuclear fusion and nuclear fission reactions. 2. Describe a chain reaction. 3. Describe the components of a nuclear fission reactor. 4. Compare and contrast the process, risks, and benefits of the production of nuclear energy via nuclear fission vs. nuclear fusion.
Written Work
Chapter 4: p. 122-124 #41, 44, 49, 52, 54, 65, 76, 81, 84, 85, 86 p. 125-126 #1-6
Chapter 25: p. 821-823 #25, 29(a,b), 30(a,b), 31(a-c), 34, 35(ab), 38, 47(a-c), 51(a-d), 52(b), 55, 67, 68, 70, 72 p. 825 #1, 9, 13 Supplemental Questions
This work will now be due two days before your next test to allow enough time evaluation and return
1. One of the most fascinating experiments that led to a better understanding the electron was conducted by Robert Millikan.
a. Briefly describe his experiment and give it a try using the simulator found on the following website: http://www.montereymotiongraphics.com/example1.swf
b. Using Thomson’s charge to mass ratio of the electron (1g = 1.76 x 108 Coulombs) and Millikan’s charge on the electron (1.5924 x 10-19 Coulombs), calculate the mass of a single electron. Use factor-label please
2. James Chadwick was responsible for the discovery of the neutron. Prior to Chadwick’s discovery, the atom was only thought to contain protons and electrons. Interestingly enough, the mass of the atom was known, but something just didn’t add up: namely, the mass of all the protons and electrons in an atom did not add but to be equal to the mass of the atom.
a. The mass of a proton is 1.0073amu. The mass of a neutron is 1.0086amu. Determine the mass of carbon-12 (in amu) based on these values.
b. The actual mass of carbon-12 is 12amu. Go to http://www.colorado.edu/physics/2000/periodic_table/amu.html and read about “mass defect”. At the bottom of the page, click on the “nuclear energy” link and read about binding energy.
Explain why the mass of carbon-12 does not equal the sum of its parts in terms of mass defect and binding energy. 3. Go to http://www.periodictable.com/index.html to answer the following questions.
a. Locate element #60, neodymium on the periodic table. What period does it reside in?
b. Click on neodymium, at the top of the neodymium page click on “neodymium isotope data”. How many different isotopes of neodymium are there?
c. Which isotopes account for the atomic mass of neodymium?
d. Why don’t the other isotopes contribute to the atomic mass of neodymium?
e. Calculate the neutron to proton ratio for the 7 isotopes that contribute most to the mass of neodymium.
f. Plot the approximate location of Nd-124, Nd-145, and Nd-161 on the band of stability graph below.
g. Unstable isotopes will often undergo a series of decay reactions until a stable isotope is formed. Write the first reaction in the decay series for both Nd-124 and Nd-161, showing the parent nuclide and the reaction products.
h. Based on the half-life of Nd-124, how long would it take for 128g of the isotope to decay leaving only 16g to remain. 4. How long would it take for a 235 g sample of Bi-186 to decay to 18g if the half life of this isotope is 14.8ms. Report your answer in microseconds. (see power point slide on the use of natural logs for help)
5. Using the figure to the right, list each type of decay that uranium-238 goes through to become lead-206.
6. Thorium-232 undergoes radioactive decay until a stable isotope is reached. Write the reactions for the decay of Th-238. There are eleven steps beginning with Alpha decay with each product becoming the reactant of the next decay. Circle the final Stable isotope.
• Alpha: • Beta: • Beta: • Alpha: • Alpha: • Alpha: • Alpha: • Beta: • Beta: • Alpha: • Beta: ______7. One of the elusive quests of ancient alchemists was to “manufacture” gold. Although we have the ability to induce transmutation of elements, the cost of producing gold in this way would far outweigh the value of the gold itself. However, this should not keep you from experiencing some “funstration” as you attempt to solve the following theoretical problems.
Gold can currently be manufactured in a nuclear reactor by irradiation either of platinum or mercury. Since platinum is more expensive than gold, platinum is economically unsuitable as a raw material. Only the mercury isotope Hg-196, which occurs with a frequency of 0.15% in natural mercury, can be converted to gold by neutron capture, forming Hg-197 which naturally decays to Au-197.
a. Write the transmutation reaction of Hg-196 into Au-197, with the decay of Hg-197 as an intermediary step.
b. What mass of natural mercury would be required to produce 1 x 109 Au-197 atoms? (1Au-197 atom = 3.27 x 10-22g, 1Hg-196 atom = 3.25x10-22g)
c. How much would this amount of mercury cost if 1L of mercury costs $2000.00 and the density of mercury is 5.43g/cm3?
8. Using the internet as a resource, research a treatment for a medical condition that uses radioactive isotopes. Briefly state the isotopes used and the process by which they work to treat the condition.
This is the end of the supplemental questions Atomic Particle Worksheet
Complete the chart by filling in the missing information. Assume neutral atoms.
Name of Isotope Atomic Mass Number of Number of Number of element Symbol Number Number protons Electrons Neutrons 12 C 6
Helium-4
30 35
Gold-197 79
16 O 8
207 82
53 127
19 20
Atomic Mass Problems
1. Calculate the average atomic mass of sulfur if 95.00% of all sulfur atoms have a mass of 31.972 amu, 0.76% has a mass of 32.971amu and 4.22% have a mass of 33.967amu.
2. There are three isotopes of silicon. They have mass numbers of 28, 29 and 30. The average atomic mass of silicon is 28.086amu. What does this say about the relative abundances of the three isotopes?
3. The atomic mass of bromine is 79.904amu. One isotope of bromine has an atomic mass of 78.92amu and a relative abundance of 50.69%. The other major isotope of bromine has an atomic mass of 80.92amu. What is the relative abundance of the second isotope? Nuclear Decay Reactions
Complete the following nuclear equations and state the type of nuclear decay. 210 4 1. 84Po______ 2 He ______8 8 2. 5B 4 Be ______234 0 3. ______91Pa 1 e ______14 0 4. 6C______ 1 e ______81 81 5. ______37Rb 36 Kr + X-ray photon ______15 15 6. 8O� 7 N ______58 0 7. 28Ni+ - 1 e ______226 222 8. 88Ra 86 Rn ______ ______1 0 9* 0n_____ 1 e ______238 4 10. 92U______ 2 He ______
Complete the following nuclear equations. 9 4 1 18 17 11. 4Be 2 He _____ 0 n 20. 9F 8 O _____ 239 0 2 4 1 12. ______94Pu 1 e 21. 1H_____ 2 He 0 n energy 66 66 27 0 13. 29Cu 30 Zn ______22. 14Si 1 e ______27 30 1 4 210 14. 13Al______ 14 Si 1 H 23. ______2He 81 Tl 141 0 32 0 15. 56Ba______ 1 e 24. 15P______ 1 e 4 17 1 142 142 16. ______2He 8 O 1 p 25. 61Pm+ _____ 60 Nd 181 4 14 14 1 17. ______77Ir 2 He 26. 7N_____ 6 C 1 p 241 237 13 1 18. 95Am_____ 93 Np 27. 6C 0 n ______12 246 239 4 1 1 19. ______6C 98 Cf n 28. 94Pu 2 He 1 H 2 0 n ______
Using your knowledge of nuclear chemistry, write the equations for the following processes:
1) The alpha decay of iridium-174
2) The beta decay of platinum-199
3) Positron emission from sulfur-31
4) Krypton-76 undergoes electron capture Half Life Problems
1) A certain isotope has a half-life of 6.00 hours. How much of a 5.00g sample will be left after 24 hours?
2) A certain isotope has a half-life of 3.25 hours. How much of a 10.0kg sample will be left after 3 days?
3) Carbon-14 has a half-life of 5730 years. How long will it take for a 1.00kg sample to be reduced to 0.25kg of carbon-14?
4) A certain isotope of Uranium has a half-life of 4.3 billion years. How long will it take for a 2.7g sample to be reduced to 0.0844g?
5) A 0.40g sample of thorium-228 is reduced to 0.05g in 5.7 years. What is the half-life of thorium-228?
6) A sample of radon-222 is found to have decreased from 266g to 8.5g in 19 days. Calculate the half- life of radon-222.
7) An isotope with a half-life of 8 hours was received exactly 24 hours before it was to be used. At the time of use, the quantity of the isotope was 16.5g. How much of the isotope was there upon delivery to the lab?
8) How long will a 12.4g sample of a radioisotope take to decay to 1.55g if its half-life is 1.2 days? Induced Transmutation Reactions Write the following reactions from the given information
1. Alpha particle bombardment of einsteinium-253 (one of the products is a neutron).
2. Induced transmutation of uranium-238 into californium-246 by bombardment with carbon-12.
3. One induced transmutation reaction of uranium-235 with a neutron results in the release of three neutrons and the production of two new nuclides. One of the nuclides is xenon-138. Write the equation with both reactants and all three products.
4. Bombardment of uranium-235 with a neutron can generate tellurium-135, 3 neutrons, and one other product. Write the complete reaction for this transmutation.
5. The first radioactive nucleus produced in the laboratory was phosphorus-30. Another product of this reaction was a neutron. This was accomplished through alpha bombardment. Write the complete transmutation reaction including original isotope.
6. When sodium-23 combines with hydrogen-2, an alpha particle is produced along with a new nuclide. Write the complete equation for this fusion reaction.