| A | B |
|---|
| radioactivity | decay of unstable nuclei to produce alpha particles, beta particles, and gamma rays |
| beta particle | high-energy electron emitted from the nucleus when a neutron changes to a proton |
| gamma ray | high-energy electromagnetic radiation produced by decaying nuclei |
| fission | nuclear reaction in which a very heavy nucleus splits into 2 smaller nuclei of approximately equal mases |
| chain reaction | self-sustaining nuclear or chemical reaction in which the product from one step acts as a reactant for the next step |
| positron | an antiparticle of an electron released during radioactive decay |
| half-life | time it takes for one half of a sample to decay |
| fusion | two light nuclei combine to make one heavire nucleus |
| alpha particle | a helium nucleus |
| mass number | # protons + # neutrons |
| atomic number | # protons |
| isotopes | atoms that have the same number of protons, but different numbers of neutrons |
| radiocarbon dating | a way to date once living objects based on the half-life of carbon--14 |
| nuclide | general term applied to each unique atom, identified by the number of protons and neutrons in its nucleus |
| nuclear radiation | particles or electromagnetic radioation emitted from the nucleus during radioactive decay. |
| radioactive decay | spontaneous disintegration of a nucleus into a slightly lighter nucleus |
| transmutation | a change in the identity of a nucleus as a result of a change in the number of its protons |
| transuranium elements | Elements with more than 92 protons in their nuclei, not found naturally on Earth |
