1. RADIOACTIVITY REVIEW

2. 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.

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.
1:1.5+ ratio of protons to neutrons
1:1.5 or less ratio of protons to neutrons
Nucleus decays
Nucleus 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. 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

8. REVIEW

9. REVIEW

10. 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.

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. 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!

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.
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.

18. 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

19. 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

20. REVIEW - WATCH
What is radioactive decay?