1. Warm-Up 10/23/13
Hold Tight! We are changing the seating chart slightly.
REMINDER: All warm-ups need to be in your folder by Friday in order to be graded.

2. Radioisotopes and Radioactivity
Wednesday 10/23/13

3. Radioisotopes
Some isotopes are too large, and called radioisotopes. They are described as being “unstable.”
Radioisotopes become stable by emitting large amounts of energy (radiation) breaking apart.

4. Radioactivity
A term coined my Marie Curie in 1869 after discovering uranium ore emits rays.
It is the process of gaining stability by “radioactive decay”—emitting large amounts of energy to become stable.

6. Radiation
Radiation is the penetrating rays and particles emitted by a radioactive source.

7. Stability The stability of the nucleus of an atom depends on:
Proportion of neutrons to protons in the nucleus
The overall size of the nucleus

8. Types of Radiation
There are different methods for becoming a stable nuclei
Alpha
Beta
Gamma
Electron Capture
Positron Emission

9. Alpha Decay
Helium nuclei (Alpha Particles) emitted to decrease protons and neutrons
Large particles, blocked by paper or skin
𝑈 → 𝑇ℎ 𝐻𝑒

10. Beta Decay
Electrons (beta particles) released in break down of neutrons (n0 to p+ + e-)
Smaller particles, blocked by foil or thin wood
6 14 𝐶 → 𝑇ℎ + −1 0 𝑒

11. Gamma Decay
High energy (not particles) often emitted along with alpha or beta decay. Does not change atomic # or mass. Like x-rays!
Dangerous, stopped by meters of concrete or cm’s of lead
𝑃𝑢∗ → 𝑃𝑢 𝛾

12. 28 59 𝑁𝑖+ −1 0 𝑒 → 27 59 𝐶𝑜 Electron Capture
Electrons captured by the nucleus to convert a proton to a neutron (better n/p ratio).
28 59 𝑁𝑖+ −1 0 𝑒 → 𝐶𝑜

13. 5 8 𝐵 → 4 8 𝐵𝑒 + +1 0 𝑒 Positron Emission
A positron (opposite of an electron) emitted to convert a proton to a neutron (better n/p ratio)
5 8 𝐵 → 4 8 𝐵𝑒 𝑒

14. Practice From Back Side…

15. Your Job Finish the problems on the back! We will check them tomorrow.
QUIZ Friday on stuff from today!