Teacher: Mr. gerraputa Print Close Name: 1 Which two radioisotopes have the same decay mode? 37 Ca and 53 Fe 220 Fr and 60 Co 37 K and 42 K 99 Tc and 19 Ne 1 5. 3 Exactly how much time must elapse before 16 grams of potassium-42 decays, leaving 2 grams of the original isotope? 6. 4 8!136 hours 2!136 hours 3!136 hours 4!136 hours In the reaction: an alpha particle an electron a beta particle a proton 2 Given the equation:, the X represents The spontaneous decay of an atom is called ionization combustion crystallization transmutation 7. 4 Which nuclear equation represents a natural transmutation? When the equation is balanced correctly, which particle is represented by X? 8. 3 2 Based on Reference Table N, what fraction of a sample of gold- 198 remains radioactive after 695 days? Which subatomic particle has no charge? alpha particle neutron beta particle electron Page 1 of 7
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9. 1 An original sample of K-40 has a mass of 25.00 grams. After 9! 10 9 years, 125 grams of the original sample remains unchanged. What is the half-life of K-40? 10. 1 3! 10 9 y 6! 10 9 y 9! 10 9 y 2! 10 10 y Which reaction illustrates fusion? 1 Polonium-210 occurs naturally, but is scarce. Polonium-210 is primarily used in devices designed to eliminate static electricity in machinery. It is also used in brushes to remove dust from camera lenses. Polonium-210 can be created in the laboratory by bombarding bismuth-209 with neutrons to create bismuth-210. The bismuth- 210 undergoes beta decay to produce polonium-210. Polonium- 210 has a half-life of 138 days and undergoes alpha decay. Figure 1 Determine the total mass of an original 28.0-milligram sample of Po-210 that remains unchanged after 414 days. Answer: 5 mg 1 2 In the equation: 1 1, the symbol X represents An unstable nucleus loses the most mass if the nucleus emits an alpha particle a positron a beta particle a gamma ray 1 4 Atoms of I-131 spontaneously decay when the 15. 3 stable nuclei emit alpha particles stable nuclei emit beta particles unstable nuclei emit alpha particles unstable nuclei emit beta particles Which nuclear reaction is classified as alpha decay? Page 3 of 7
16. 2 Which radioisotope is used to treat thyroid disorders? Co-60 C-14 I-131 U-238 17. 1 Which type of radioactive emission has a positive charge and weak penetrating power? alpha particle gamma ray beta particle neutron 18. 4 The chart below shows the spontaneous nuclear decay of U-238 to Th-234 to Pa-234 to U-23 19. Base your answer to this question on the information below. The radioisotope uranium-238 occurs naturally in Earth s crust. The disintegration of this radioisotope is the first in a series of spontaneous decays. The sixth decay in this series produces the radioisotope radon- 22 The decay of radon-222 produces the radioisotope polonium-218 that has a half life of 04 minutes. Eventually, the stable isotope lead-206 is produced by the alpha decay of an unstable nuclide. Figure 2 Determine the original mass of a sample of Po-218, if 0.50 milligram of the sample remains unchanged after 116 minutes. Answer: 8.00 mg 20. 4 Given the balanced equation representing a nuclear reaction: Which particle is represented by X? What is the correct order of nuclear decay modes for the change from U-238 to U-234? " # decay, $ decay, " # decay " # decay, " # decay, % decay % decay, % decay, " # decay % decay, " # decay, " # decay 2 2 Which particle is emitted when an atom of 85 Kr spontaneously decays? an alpha particle a neutron a beta particle a proton Page 4 of 7
2 2 What is the total mass of 222 Rn remaining in an original 160-milligram sample of 222 Rn after 19.1 days? 5 mg 10. mg 5.0 mg 20. mg 2 2 The diagram represents radioactive emanations passing through an electric field. Which type of emanation is represented by the arrow labeled 1? alpha particle positron beta particle gamma ray Page 5 of 7
2 1 25. 1 Radioactivity at home You may be surprised to learn that you do not need to visit a nuclear power plant or a hospital X-ray laboratory to find sources of radioactivity. They are all around us. In fact, it is likely that you ll find a few at home. Your front porch may incorporate cinder blocks or granite blocks. Both contain uranium. Walk through the front door, look up, and you ll see a smoke detector that owes its effectiveness to the constant source of alpha particle emissions from Americium-24 As long as the gases remain ionized within the shielded container, electricity flows, and all is calm. When smoke enters the chamber, it neutralizes the charges on these ions. In the absence of these ions, the circuit breaks and the alarm goes off. Indicator lights on your appliances may use Krypton-85; electric blankets, promethium- 147; and fluorescent lights, thorium-229. Even the food we eat is radioactive. The more potassium-rich the food source, the more potassium-40 a radioactive isotope that makes up about 0.01% of the natural supply of this mineral is present. Thus, brazil nuts, peanuts, bananas, potatoes, and flour, all rich in potassium, are radiation sources. Chem Matters, April 2000 Figure 3 Base your answer to the question on the article, the Reference Tables for Physical Setting/Chemistry, and your knowledge of chemistry. Which of the following is the equation for the alpha decay that occurs in a smoke detector containing Americium-241 (Am- 241)? Which change takes place in a nuclear fusion reaction? 26. 2 Matter is converted to energy. Energy is converted to matter. Ionic bonds are converted to covalent bonds. Covalent bonds are converted to ionic bonds. Which nuclide is a radioisotope used in the study of organic reaction mechanisms? carbon-12 uranium-235 carbon-14 uranium-238 27. 2 The change that is undergone by an atom of an element made radioactive by bombardment with high-energy protons is called natural transmutation artificial transmutation natural decay radioactive decay 28. 3 Which nuclide is paired with a specific use of that nuclide? 29. 1 If carbon-14, treatment of cancer cobalt-60, dating of rock formations iodine-131, treatment of thyroid disorders uranium-238, dating of once-living organisms of an original sample of krypton-74 remains unchanged after 35 minutes, what is the half-life of krypton-74? 15 min 35 min 20 min 46.0 min Page 6 of 7
30. 3 Which list of radioisotopes contains an alpha emitter, a beta emitter, and a positron emitter? C-14, N-16, P-32 Kr-85, Ne-19, Rn-222 Cs-137, Fr-220, Tc-99 Pu-239, Th-232, U-238 Page 7 of 7