| A | B |
|---|
| Isotopes | Atoms of the same element that have different numbers of neutrons. |
| Proton | Positively charged particle in the nucleus of an atom. |
| Transmutation | The changing of one element into another through radioactive decay. |
| Radioactive decay | Release of nuclear particles and energy from unstable atomic nuclei. |
| Electron | Negatively charged particle that exists in an electron cloud formation around an atom's nucleus. |
| Element | Substances that cannot be broken down into simpler substances. |
| Neutron | Electrically neutral particle that has the same mass as a proton and is found in an atom's nucleus. |
| Half Life | Time needed for one-half of the mass of a sample of a radioactive isotope to decay. |
| Mass number | The sum of neutrons and protons in the nucleus of an atom. |
| Atomic number | Number of protons in the nucleus of an atom of a given element. |
| Electron cloud | Region surrounding the nucleus of an atom, where electrons are most likely to be found. |
