1. Nuclear Chemistry
Chapter 21

2. Objectives Define radioactivity.
Explain trends in the relative stability of nuclei.
Complete half-life calculations.
Write, balance, and interpret nuclear reactions.
Identify types of radioactive decay.
Explain how fusion and fission occur.
Discuss applications of nuclear chemistry in everyday life.
Outline the potential hazards of nuclear energy.

3. Chemical Reactions vs Nuclear Reactions

4. Nuclear Reactions The mass must be conserved
The atomic number must be conserved.

6. Nuclear Stability
Certain numbers of neutrons and protons are extra stable
n or p = 2, 8, 20, 50, 82 and 126
Like extra stable numbers of electrons in noble gases (e- = 2, 10, 18, 36, 54 and 86)
Nuclei with even numbers of both protons and neutrons are more stable than those with odd numbers of neutrons and protons
All isotopes of the elements with atomic numbers higher than 83 are radioactive
All isotopes of Tc and Pm are radioactive

8. Types of Nuclear Decay

9. Energy of Radioactivity

10. Nuclear Stability and Radioactive Decay
Beta decay
14C N + 0b 6 7 -1
Decrease # of neutrons by 1
40K Ca + 0b 19 20 -1
Increase # of protons by 1
1n p + 0b 1 -1
Positron decay
11C B + 0b 6 5 +1
Increase # of neutrons by 1
38K Ar + 0b 19 18 +1
Decrease # of protons by 1
1p n + 0b 1 +1

11. Nuclear Stability and Radioactive Decay
Electron capture decay
37Ar + 0e Cl 18 17 -1
Increase number of neutrons by 1
55Fe + 0e Mn 26 25 -1
Decrease number of protons by 1
1p + 0e n 1 -1
Alpha decay
Decrease number of neutrons by 2
212Po He + 208Pb 84 2 82
Decrease number of protons by 2
Spontaneous fission
252Cf In + 21n 98 49

13. Complete the following nuclear reaction equations.

14. Complete the following nuclear reaction equations.
Alpha decay for Thorium-232
Plutonium-244 undergoes beta decay
Radon-222 decays into Astatine-210
Francium-223 emits a gamma particle
Complete the following nuclear reaction equations.

15. What Are Your Questions?

16. What is Half-Life?
The amount of time it takes for half a given amount of material to radioactively decay into something else.

17. Initial Amount
After 1 Half-Life
After 2 Half-Lives
After 3 Half-Lives

18. Based solely on the following half-lives, which radioactive atom listed is the most radioactive?
C-14 (5730 yrs)
Ra-226 (1620 yrs)
U-238 (4.5 million yrs)
Po-214 (1.6 ms)
P-32 (14 days)

19. Radioactive Dating Radiocarbon Dating 14N + 1n 14C + 1H7 1 6
14C N + 0b + n 6 7 -1
t½ = 5730 years
Uranium-238 Dating
238U Pb + 8 4a + 6 0b 92 -1 82 2
t½ = 4.51 x 109 years = t½ l
0.693

20. A 4. 5 gram sample of radon decomposes over 3 half lives
A 4.5 gram sample of radon decomposes over 3 half lives. How much of the sample remains?

21. The half-life of C-14 is 5730 years
The half-life of C-14 is 5730 years. How long will it take for 50% of 25g of C-14 to decompose? How long will it take for 75% to decompose?

22. An artifact contains 12. 5% of the original amount of C-14
An artifact contains 12.5% of the original amount of C-14. How old is this sample? (C-14 half-life is 5730 years.)

23. The half-life of the beta particle emitter tritium, 3H, is 12 years
The half-life of the beta particle emitter tritium, 3H, is 12 years. How much of a 1.00 g sample of 3H remains after 48 years?

24. What Are Your Questions?

25. Fusion and Fission

26. Nuclear Fusion Reactor

27. Medical Uses for Radioactive Isotopes

28. Nuclear Weapons Use nuclear reactions to create an intense explosion.
The Manhattan Project
Project the ran from to develop atomic bombs.

29. Nuclear Disasters Three Mile Island (1979) Chernobyl (1986)
Partial Meltdown in Pennsylvania
Chernobyl (1986)
Reactor 4 meltdown in Ukraine
Time 3:06
Fukushima (2011)
Three of six nuclear reactors melted down in Japan as a result of a tsunami

30. What Are Your Questions?