1. Nuclear Chemistry
Nuclear Reactions involve an atom’s nucleus !!!!

2. Radioactive Decay Spontaneous breakdown of an atom’s nucleus
Breakdown results in a lighter nucleus
Emits electromagnetic radiation
Nuclear radiation—radiation emitted from nucleus
Radioactive nuclide– nucleus that goes through radioactive decay, unstable. (Ex. Uranium
Ask where are our nuclear power plants in NC?
Nucleii beyond 83—unstable, radioactive

3. Types of Radioactive Decay
Alpha particle (α)
Consists of 2 protons, 2 neutrons emitted during decay
Helium nucleus ( 24He )—how particle represented
Can be stopped by paper, low energy
Atomic number goes down 2, atomic mass goes down 4.
Equation: Po  Pb + 24 He
Beta particle (β)
Electron given off during radioactive decay
Can be stopped by lead or glass
Increase in atomic #
Equation: 614 C  714 N β
Gamma Rays
Has the most energy, only stopped by lead
Ex. X-Rays
Alpha particles are heavy—stopped by paper.
Beta particles are lighter—more penetrating power
Gamma particles—go through anything (ex. X-ray)---have to wear lead apron.

4. Example 1: Nuclear equation when an alpha particle emitted by 21084Po

5. Example 2:Nuclear equation when a beta particle emitted by 21082Pb

6. Practice: Alpha Decay
Be-9
U-238
Eu-154
Beta Decay
Th-234
K-43

7. Half-Life
Time period required for half of a radioactive nuclide to decay.
Vary depending on the nuclide, unique for each nuclide.
Ex. 146C has a half-life of Therefore, if we have 10g of 146C, in 5715 years we will have 5g.

8. Exponential
From Google images

9. Decay series

10. AE = AO * 0.5 t/t(1/2) Half-Life Equation AE = Substance amount
A0 = Initial substance amount
t = time elapsed
t1/2 = half-life

11. Example 1: Plutonium-239 has a half life of 24,110 years
Example 1: Plutonium-239 has a half life of 24,110 years. We have 100g of this substance. How many grams will we have after 96,440 years?
6.25g

12. More on Nuclear Chemistry

13. Nuclear Fission Nuclear reaction where nuclei are SPLIT
Nucleus is broken down into a more stable nucleus.
HUGE amount of energy is released
Critical mass = minimum number of nuclei that can provide enough neutrons to maintain chain reaction.
Nuclear reactors = controlled fission reactions.
**Can induce a nuclear chain reaction!!!
Neutrons bombard atom, nucleus splits—produces more neutrons that can then attack other atoms—chain reaction!
Reaction continues until all nuclei are split.
Happens with Uranium 235
**Type of reaction used in nuclear power plants!!!

14. Uranium-235 used
HUGE, HUGE, HUGE amount of water is used to cool the reactors !!!!!

15. Nuclear Reactors Location where controlled fission reactions occur
Fuel rods in the core contain enriched uranium
Steam generation steam turbine electric generator
Control rods take in neutrons so fission is controlled
Production of radioactive waste
A TON of water is used to cool the reactors

17. Nuclear Fusion Nuclei having a light mass are joined.
Combination of light nuclei
Creates heavy nucleus
Results in larger, stable nucleus.
MORE energy released than in nuclear fission !!!
Hard to control
Initiated by fission reaction (fission bomb) ---- H bomb
**Type of reaction happening in the sun and stars.
-fuel: hydrogen atom
Fission reaction used to start a fusion reaction in H bomb.

18. Atomic bomb--

19. cu
H bomb
Fusion reaction generated from a fission reaction

20. Applications to Nuclear Radiation
Radioactive Dating
Age determination of artifact based on presence of radioactive nuclide
Medical Purposes
Cancer treatments
Radioactive tracers
Food Processing
Meat exposed to radiation
Kills microorganisms

21. Prompt
We talked about nuclear energy today. Do you support or disagree with this type of green energy? Support your answer.
How could we harness the nuclear energy in the sun? Discuss how we might use nuclear fusion to benefit us.