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Sciense 4A
| Question | Answer |
|---|---|
| radioactivity | the process by which an unstable nucleus gives off nuclear radiation |
| mass number | the sum of the numbers of protons and neutrons in the nucleus of an atom |
| isotope | an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass) |
| Half-life | the time needed for half of a sample of radioactive substance to undergo radioactive decay |
| nuclear fission | the splitting of the nucleus of a large atom into two or more fragments; realesed additional neutrons into energy |
| nuclear chain reaction | a continuos serious of nuclear fission reactions |
| Beta Particle | Has a mass of zero and has no protons or neutrons |