| Term | Definition |
|---|---|
| Nucleus | The center of an atom. |
| Atom | Basic unit of all matter. |
| Element | A substance made of only one kind of atom. |
| Matter | Anything that has a mass and a volume. |
| Proton | Positively charged particle in an atom. |
| Substance | Is matter with a composition that is always the same. |
| Heterogeneous | A mixture that is not evenly mixed. |
| Homogeneous | A mixture that is evenly mixed. |
| Electron | the negatively charged particle in an atom. |
| Neutron | The neutral particle in an atom |
| Ion | An atom with a charge |
| Isotope | An atom with a different number of neutrons. |
