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. Types of Decay Alpha Beta Gamma Like He Nucleus Low Energy
Blocked by paper & skin
Fast-moving e-
Blocked by Al foil, clothing, wood
No mass, no charge
Accompanies alpha/beta
High energy
Mostly blocked by thick Pb & concrete

5. 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.

6. Exponential
From Google images

7. Decay series

8. Initial amount of sample
Half-Life
Time it takes for ½ of a sample to decay.
Need 3 out of 4 to solve:
**May also need to figure out # of ½ lives**
Initial amount of sample
Final amount of sample
Length of ½ life
Total time measured

9. 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

10. 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

11. Half-Life Examples
12) Gold-191 has a half life of 12.4 hrs. What mass of this isotope would remain after 49.6 hrs if you started with a 7.50 mg sample?

12. Half-Life Examples
3) What is the half-life of an isotope of plutonium, if the original sample was 10.0g and after 420 days there was 1.25 grams?

13. Nuclear Reactions

14. Nuclear Fission Nuclear reaction where nuclei are SPLIT
Nucleus is broken down into a more stable nucleus.
HUGE amount of energy is released
**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!!!

15. Chain Reaction

16. Uranium-235 used
HUGE, HUGE, HUGE amount 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. 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