| 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 |
| alpha decay | the release of an alpha particle from a nucleus |
| alpha particle | a type of nuclear radiation consisting of two protons and two neutrons emitted by the nucleus of a radioactive atom; identical to the nucleus of a helium atom |
| mass number | the sum of the protons and neutrons in an atom |
| radioactive decay | the process in which the nucleus of a radioactive atom releases nuclear radiation |
| beta decay | the release of a beta particle from a nucleus |
| gamma decay | the release of gamma rays from a nucleus |
| gamma rays | EM waves with very high energy and no mass or change; they are emitted by the nucleus of a radioactive atom |
| isotopes | atoms that have the same number of protons but have different numbers of neutrons |
| positron | a beta particle with a charge of 1+ and a mass of almost 0 |
| half-life | the amount of time it takes for one-half of the nuclei of a radioactive isotope to decay |
| tracer | a radioactive element whose path can be followed through a process or reaction |
| nuclear fission | the process in which a large nucleus splits into smaller nuclei |
| nuclear chain reaction | a continuous series of nuclear fission reactions |
| nuclear fusion | the process in which two or more nuclei with small masses join together, or fuse, to form a larger, more massive nucleus |
