| A | B |
| nuclear radiation | high-energy particles and rays that are emitted by the nuclei of some atoms' alpha particles, beta particles, and gamma rays are types of nuclear radiation |
| radioactivity | the ability of some elements to give off nuclear radiation |
| radioactive decay | the process in which the nucleus of a radioactive atom releases nuclear radiation |
| alpha decay | the release of an alpha particle from a nucleus |
| mass number | the sum of the protons of neutrons in atom |
| beta decay | the release of a beta particle from a necleus |
| isotopes | atoms that have the same number of protons but have different numbers of neutrons |
| gamma decay | the release of gamma rays from a nucleus |
| half-life | the amount of time it takes for one-half the nuclei of a radioactive isotope to decay |
| neclear fission | the process in which a large nucleus splits into two smaller nuclei; during this process, matter in converted into energy |
| nuclear chain reaction | a continuous series of nuclear fission reactions |
| nuclear fusion | the process in shich two or more nuclei whith small masses join together, or fuse, to form a larger, more massive nucleus; during this process, matter is converted into energy |