Name: ____________________________________________ Date: _________________ Period: ______
Chemistry Worksheet
Radioactivity, Decay, and Half-Life
1. Define the term “radioactivity.”
2. Give an example of a radioactive nucleus.
3. Why is the nucleus considered to be radioactive?
4. What does the uranium-238 atom do to become a thorium-234 atom?
5. What is the eventual fate of uranium-238?
6. How long does it take for a uranium-238 sample to completely decay to thorium-234?
7. Unstable isotopes emit radioactive decay in what three forms?
8. What happens when a radioactive isotope undergoes alpha decay?
9. Give an example of alpha decay.
10. What happens when a radioactive isotope undergoes beta decay?
11. Give an example of beta decay.
12. What happens when a radioactive isotope undergoes gamma decay?
13. Give an example of gamma decay.
14. Gold-185 decays to Iridium-181. Which type of decay is this, and why?
15. List four facts about the Sun and solar energy.
16. How does a nuclear reactor generate electricity?
17. The United States gets about _______% of its energy each year from nuclear reactors.
18. What occurs as a radioactive element decays?
19. All radioactive elements have a ______________________.
20. Define the term “half-life.”
21. What is the half-life of carbon-14?
22. Explain what is meant by the answer to Question 21.
23. Nuclear reactors produce _____________________________.
24. What fuel is used in a nuclear reactor? ___________________.
25. What occurs when uranium atoms undergo nuclear fission?
26. List two characteristics of the smaller atoms that result from uranium fission.
27. What is the consequence of the answer to Question 26?
28. What is the current situation regarding nuclear waste storage?
29. Fully describe the process of carbon-14 dating.
30. Do all radioactive isotopes decay at the same rate? __________
31. How is half-life actually calculated?
32. Describe the half-life sequence of radium-226.
33. _________________ nuclides decay slowly and have ________________________.
34. _________________ nuclides decay very quickly and have _____________________,
sometimes just ________________________.
35. Practice with Half-Life: Phosphorus-32 has a half-life of 14.3 days. How many milligrams of
phosphorus-32 remain after 57.2 days if you start with 4.0 mg of the isotope?