1. © Copyright Pearson Prentice Hall Radioactivity

2. © Copyright Pearson Prentice Hall Chemistry Joke Q: What do you get when you put Jim Carrey in jail? A: Si

3. © Copyright Pearson Prentice Hall The presence of too many or too few neutrons relative to protons can cause a nucleus to be unstable. An unstable nucleus will change to become stable. This process of radioactivity releases a lot of energy Also called radioactive decay

4. © Copyright Pearson Prentice Hall Radioactivity produces both penetrating rays and particles. The particles and rays are called radiation.

5. © Copyright Pearson Prentice Hall –Alpha –Beta –Gamma 3 Types of Radiation

6. © Copyright Pearson Prentice Hall Alpha Radiation Helium nuclei that have been emitted from a radioactive source. These emitted particles are called alpha particles. Contain two protons and two neutrons—very heavy Have a double positive charge. ++

7. Slide 7 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation Equation:

8. © Copyright Pearson Prentice Hall Beta Radiation An electron resulting from the breaking apart of a neutron in an atom is called a beta particle.

9. Slide 9 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Equation:

10. © Copyright Pearson Prentice Hall Gamma Radiation A high-energy photon emitted by a radioisotope is called a gamma ray. Often emitted with either alpha or beta particles. Has no mass or charge

11. © Copyright Pearson Prentice Hall Alpha particles are the least penetrating. Gamma rays are the most penetrating. Penetrating Power

12. © Copyright Pearson Prentice Hall Slide 12 of 21 Section Quiz. 1.An unstable nucleus releases energy by a.emitting radiation. b.thermal vibrations. c.a chemical reaction. d.giving off heat.

13. © Copyright Pearson Prentice Hall Slide 13 of 21 Section Quiz. 2.Which property does NOT describe an alpha particle? a.2+ charge b.a relatively large mass c.a negative charge d.low penetrating power

14. © Copyright Pearson Prentice Hall Slide 14 of 21 Section Quiz. 3.When a radioactive nucleus releases a high- speed electron, the process can be described as a.oxidation. b.alpha emission. c.beta emission. d.gamma radiation.

15. © Copyright Pearson Prentice Hall Slide 15 of 21 Half-Life Section A half-life (t 1/2 ) is the time required for one- half of a radioisotope sample to decay to products. –After each half-life, half of the existing radioactive atoms have decayed into atoms of a new element.

16. © Copyright Pearson Prentice Hall Slide 16 of 21 Half-Life

17. © Copyright Pearson Prentice Hall Slide 17 of 21 Half-Life

18. © Copyright Pearson Prentice Hall Slide 18 of 21

19. © Copyright Pearson Prentice Hall Slide 19 of 21

20. © Copyright Pearson Prentice Hall Slide 20 of 21 10.4 h ÷ 2.6 h = 4 half lives 1.0 mg x 0.5 x 0.5 x 0.5 x 0.5 = 0.063 mg Or…1.0 mg x (0.5) 4 = 0.063 mg

21. © Copyright Pearson Prentice Hall Slide 21 of 21 – If there were 128 grams of radioactive material initially, what mass remains after four half-lives? 8 grams

22. © Copyright Pearson Prentice Hall Slide 22 of 21 Chemistry Joke Q: If the formula for water is H 2 0, what’s the formula for ice? A: H 2 0 3