| A | B |
|---|
| Matter | anything that has mass and takes up space |
| Vacuum | region of space that contains no matter |
| Element | pure substance consisting of only one type of atom |
| Compound | substance made up of two or more atoms that are chenically combined and cannot be separated by physical means |
| Atom | smallest part of an element or molecule; building blocks of all things |
| Proton | positively charged particle in the nucleus of the atom (determines the element) |
| Neutron | particles with no charge in the nucleus of every atom, |
| Electron | negatively |
| Ion | positively or negatively charged atom |
| Nucleus | center of the atom; contains most of the atom's mass |
| Atomic Number | number of protons in an atom |
| Mass Number | Total number or protons and neutrons in the nucleus of an atom |
| Isotope | atom with a different number of neutrons |
