RADIOACTIVITY REVIEW
REVIEW The nucleus is held together by the strong force. 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.
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.
ALL THE ELEMENTS HEAVIER THAN BISMUTH Bismuth is the last nonradioactive element
REVIEW 3. Contrast properties of radioactive and stable nuclei. 1:1.5+ ratio of protons to neutrons 1:1.5 or less ratio of protons to neutrons Nucleus decays Nucleus is stable
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
Two protons and two neutrons REVIEW 5. Compare and contrast alpha, beta, and gamma radiation. ALPHA BETA GAMMA Type Particle energy Charge Positive Negative Neutral Composition Two protons and two neutrons One electron Pure energy Mass 1 amu 1/1840 amu none Symbol α β γ Stopped by Paper Thin metal Thick lead or concrete Size Largest Smaller Smallest New element? Atomic # drops by two Atomic # goes up by one No change
REVIEW
REVIEW
REVIEW 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.
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.
Make sure you can do the practice problems! REVIEW 7. Determine the half-life of a radioactive material. Make sure you can do the practice problems!
REVIEW 7. Determine the half-life of a radioactive material.
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.
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.
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.
REVIEW 11. Compare and contrast nuclear fission and nuclear fusion. Involves One nucleus becoming two Two nuclei becoming one Energy released Less 3-4 times more Where does it occur Nuclear power generators, bombs Sun Fusion fuses atomic nuclei together and Fission splits nuclei apart.
REVIEW 12. Compare the advantages and disadvantages of using nuclear energy to produce electricity. ADVANTAGES DISADVANTAGES No fossil fuels Mining can damage environment No air pollutants Produces heat pollution in the water used to cool Cheap to produce electricity Expensive to build plants More energy available Accidental radiation leaks No place for the waste to go to finish decaying
REVIEW catalyze (v.) to charge, inspire 13. Know the four SAT words: catalyze (v.) to charge, inspire caustic (adj.) bitter, biting, acidic effervescent (adj.) bubbly, lively frenetic (adj.) frenzied, hectic, frantic
REVIEW - WATCH What is radioactive decay?