| terms | definition |
| Nucleus | The center of an atom, made up of protons and neutrons |
| Proton | A positively charged subatomic particle in the nucleus of an atom |
| Neutron | A neutral subatomic particle in the nucleus of an atom. |
| Electron | A tiny negatively charged subatomic particle moving around outside the nucleus of an atom. |
| Energy Level | Any of the possible energies an electron may have in an atom. |
| Orbital | A region in an atom where there is a high probability of finding electrons. |
| Valence Electron | An electron in the outermost energy level of an atom. |
| Cation | An ion with a positive charge. |
| Anion | An ion with a negative charge. |
| Group ( family) | A vertical column of elements in the periodic table. |
