1. RADIOACTIVITY REVIEW

2. REVIEW 1. Review what the structure of the atom is, particularly the nucleus. Protons (+) and neutrons (o) in the nucleus Electrons (-) in the electron cloud. The nucleus is held together by the strong force.

3. REVIEW 2. Explain what radioactivity is. Radioactivity is the spontaneous emission of radiation from an element because the strong force cannot hold the nucleus together.

4. ALL THE ELEMENTS HEAVIER THAN BISMUTH Bismuth is the last nonradioactive element

5. REVIEW 3. Contrast properties of radioactive and stable nuclei. RADIOACTIVESTABLE 1:1.5 + ratio of protons to neutrons 1:1.5 or less ratio of protons to neutrons Nucleus decaysNucleus is stable

6. REVIEW 4. Know the key figures involved in the discovery of radiation. Henri Becquerel discovered mysterious rays coming from uranium. Marie and Pierre Curie discovered these rays in radium and polonium

7. REVIEW 5. Compare and contrast alpha, beta, and gamma radiation. ALPHABETAGAMMA TypeParticle energy ChargePositiveNegativeNeutral Compositi on Two protons and two neutrons One electronPure energy Mass1 amu1/1840 amunone Symbolαβγ Stopped byPaperThin metalThick lead or concrete SizeLargestSmallerSmallest New element? Atomic # drops by two Atomic # goes up by one No change

8. REVIEW

10. 6. Explain the process half-life as related to radioactive decay.  Unstable nuclei lose energy by emitting matter and energy in a spontaneous (does not require energy) process called radioactive decay.  The atom undergoes radioactive decay until it becomes stable.

11. REVIEW 6. Explain the process half-life as related to radioactive decay.  Radioactive decay rates are measured in half-lives.  A HALF-LIFE is the time it takes for one half of the radioactive sample to decay.  Different isotopes have different half-lives.

12. REVIEW 7. Determine the half-life of a radioactive material. Make sure you can do the practice problems!

13. REVIEW 7. Determine the half-life of a radioactive material.

14. REVIEW 8. Know what a Geiger counter does.  Radiation can be measure with a Geiger counter – a device that measures radioactivity by producing an electric current when radiation is present.  It produces a clicking sound.  The more clicks there are, the more radiation is being detected.

15. REVIEW 9. Explain nuclear fission and how it can begin a chain reaction. -Large nucleus splits into two smaller one, releasing energy -A CHAIN REACTION can occur is there are enough nuclei present to be split and the reaction keeps going.

16. REVIEW 10. Explain nuclear fusion and how is occurs in the sun. -Two small nuclei fuse creating one larger nucleus, releasing energy. -In the sun, several hydrogen fuse to form one helium.

17. REVIEW 11. Compare and contrast nuclear fission and nuclear fusion. FISSIONFUSION InvolvesOne nucleus becoming two Two nuclei becoming one Energy releasedLess3-4 times more Where does it occur Nuclear power generators, bombs Sun Fusion fuses atomic nuclei together and Fission splits nuclei apart.

18. REVIEW 12. Compare the advantages and disadvantages of using nuclear energy to produce electricity. ADVANTAGESDISADVANTAGES No fossil fuelsMining can damage environment No air pollutantsProduces heat pollution in the water used to cool Cheap to produce electricityExpensive to build plants More energy availableAccidental radiation leaks No place for the waste to go to finish decaying

19. REVIEW 13. Know the four SAT words: 1.catalyze (v.) to charge, inspire 2.caustic (adj.) bitter, biting, acidic 3.effervescent (adj.) bubbly, lively 4.frenetic (adj.) frenzied, hectic, frantic

20. REVIEW - WATCH What is radioactive decay?