| A | B |
|---|
| Atom | smallest unit of an element |
| Element | substances made of only one type of atom |
| Molecule | formed when two or more atoms combined |
| Compound | formed when two or more different elements combine |
| Proton | positively charged part of atom |
| Neutron | neutrally charged part of atom |
| Electron | negatively charged part of atom |
| Atomic mass | combined number of protons and neutrons in an atom |
| Atomic number | number of protons in an atom |
| Fe | iron |
| Na | sodium |
| Ag | silver |
| C | carbon |
| 12 | mass number of carbon |
| 6 | number of protons in carbon |
| Ion | electrically charged atom |
| Isotope | atom an element with a different atomic mass |
| H | hydrogen |
| He | helium |
| Mixture | combines two substances physically |
