1. Radioactivity
Chp 43

2. The early years… Mysterious “energy emanations” from some elements
3 different forms:
a which Lord Rutherford showed to be helium nuclei
b which were shown to be electrons
g which were shown to be high energy photons

3. Decay Series… Alpha Decay Beta Decay
emits alpha particle at a precise energy
beta decay does not occur at a precise energy but over a continuous range

4. Conditions for decay…

5. Why some nuclei are stable (and others not)
Consider either:
Minimum mass for a given A,Z
Maximum Eb for a given A,Z
Far away from the critical point suggests unstable nucleus
via b- decay
via b+ decay, or EC
Example: A = 200, what stable nucleus does the above graph suggest?

6. Alpha decay occurs when which occurs A > 150

7. Decay Series…

8. Uranium-238 Decay Series

9. Understanding a-Decay