Name the three kinds of strength used to characterize materials. Give examples of materials that are strong in each of these modes. What kind of chemical bonding occurs in each of these materials?

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2. Diamonds and graphite are both made from carbon atoms. Why is graphite so much weaker?
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4. How do conductors and insulators differ in their atomic structure?
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6. Explain how a semiconductor can carry an electric current.
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8. What is a semiconductor diode? How do diodes convert AC into DC?
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10. What is an isotope?
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12. What is alpha decay? Beta decay? Gamma decay? How does each of these processes change the nucleus?
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14. Explain the term half-life.
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16. What is radiometric dating? What is the most commonly used isotope in the radiometric dating of previously living organisms? Why must geologists use potassium-40 and uranium-238 instead of carbon-14 to date the oldest fossils?
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18. What is a chain reaction? What is a critical mass?
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