| A | B |
|---|
| Atom | smallest unit that maintains characteristics of an element |
| Element | substance made of only one type of atom |
| Proton | positive subatomic particle |
| Neutron | neutral subatomic particle |
| Electron | negative subatomic particle |
| Nucleus | center of an atom that contains protons and neutrons |
| Atomic Number | number of protons |
| Atomic Mass | number of protons + neutrons |
| Atomic Symbol | One or two letter abbreviation for an element name |
| Electron Cloud | Area around the nucleus where the electrons reside |
| Isotopes | Atoms of the same element with different masses an numbers of neutrons |
