1. Nuclear Chemistry Objective: To explain the process of radioactive decay using nuclear equations and half life
Essential Question: How do unstable (radioactive) isotopes become stable?

2. Review: Radioactivity introduction -
Radioactivity video – 4 minutes
Review questions:
Dig deeper:

3. Review: Radioactive Isotopes
A radioactive isotope has an unstable nucleus that undergoes spontaneous changes.
Emits particles 1. 2.
Emits energy in the form of __________ waves.
Transmutates into another element

4. Types of Radiation

5. Alpha Decay

6. Beta decay

7. Gamma Decay

8. Particles emitted from a radioactive isotope
Next slide
Type Symbol Charge Mass Rad.Strength

9. Radiation Strength: Explain in your notes how each of the radioactive emissions are blocked. Which is the most damaging (strongest)?

10. Strong Nuclear Force: Holds the nucleus together
Limit to the # neutrons: A nucleus with too many neutrons will be unstable and change

11. Balancing Nuclear Reactions
Keep track of atomic number (Z) and mass number (A): protons & neutrons
Totals of A & Z must be the same before and after the reaction.
Shown by “Before” “ After”

18. Nuclear reactions
Total number of atomic numbers and the total mass numbers must be equal on both sides of the equation. Examples:

19. Nuclear Equations Practice Website
2713Al + 42He ---> 3015P + ?
23892U  23490Th + ?
146C  0-1e + ?
23994Pu + 42He  24296Cm + ?
Nuclear Equations Practice Website

20. Nuclear Reactions Emission of Alpha or Beta particles

21. Radioactive decay
No two radioactive isotopes decay at the same rate. Therefore, decay rate can be used to identify the isotope. Decay is measured by half life.

22. Half-life Measure of Radioactive decay rate.
Measured as the time it takes for ½ of a sample of radioisotope’s nuclei to decay into its products.

23. Half Life Decay of a radioisotope Number of Half-Lives Elapsed time
Amount remaining
100 g 1
1.5 year
50 g 2
3 years
25 g 3
4.5 years
12.5 g

24. Examples of the Half Life of Radioactive Elements

25. Tearing Through a Half Life 800 Billion Bismuth-210 Atoms
Time (years)

26. Number of radioactive isotopes
Half Life:
Number of radioactive isotopes
Number of years

27. Fission and Fusion