1. QOTD How do we measure the stability of an atom?

2. Half Life Mr. Dunnum

3. Radioactivity An unstable atomic nucleus emits a form of radiation (alpha, beta, or gamma) to become stable. In other words, the nucleus decays into a different atom.

4. Radioactivity Alpha Particle – Helium nucleus Beta Particle – electron Gamma Ray – high-energy photon

5. Half-Life Amount of time it takes for one half of a sample of radioactive atoms to decay

6. Medical Applications of Half- Life NuclideHalf-LifeArea of Body I–1318.1 daysThyroid Fe–5945.1 daysRed Blood Cells Sr–872.8 hoursBones Tc–996.0 hoursHeart Na–2414.8 hours Circulatory System

7. Half-Life Calculation #1 You have 400 mg of a radioisotope with a half-life of 5 minutes. How much will be left after 30 minutes? Half-Life Calculation #1 6.25 mg

8. Half-Life Calculation # 2 In a sample of 8160g of Co-60, how much of the sample is left after 5 half-lives have passed? Half-Life Calculation #2 255g