Page 127 - Science Course 3 (Book 2)
P. 127
Mo11-L3: Key Concept Check
Direction: On the line before each statement, write T if the statement is true or F if the statement is
false.
1. Radioactive isotopes decay at a constant rate.
2. Radiometric dating involves measuring the difference between the amount of parent isotope
and daughter isotope.
3. The decay of radioactive isotopes is used to determine the size of the material in which they
are present.
4. One commonly used isotope for radioactive dating is hydrogen.
5. The ratio of C-14 to C-12 in the atmosphere is unpredictable.
6. Another name for radioactive carbon is C-14.
7. In carbon-14, there are six protons and eight neutrons in its nucleus.
8. Radiocarbons form when it mixes with C-8 in Earth’s upper atmosphere.
9. One element used by all living things to build tissue is carbon.
10. The ratio of C-14 to C-12 in the tissues of living organisms always changes.
11. The ratio of C-14 to C-12 in dead organisms stays the same.
12. One way to measure the passage of time is to determine the ratio of C-14 to C-12 in dead
organisms.
13. The half-life of uranium is 5,730 years.
14. Carbon is useful for dating remains that are more than 50,000 years old.
15. Radiometric dating must take place where the remains are discovered.
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