| A | B |
|---|
| proton | positively charged subatomic particle in nucleus of atom |
| neutron | neutral subatomic particle in nucleus of atom |
| electron | negatively charged subatomic particle outside of nucleus of atom |
| family or group | vertical column of elements in periodic table |
| ion | atom that has lost or gained one or more electrons |
| cation | ion with a positive charge |
| anion | ion with a negative charge |
| atomic number | number of protons in nucleus |
| mass number | total number of protons and neutrons in nucleus |
| isotopes | atoms of same element with same number protons but DIFFERENT NUMBER of NEUTRONS |
| metals | elements that are good conductors of heat and electricity |
| nonmetals | elements that are usually poor conductors of heat and electricity |
| alkali metals | highly reactive metallic elements in Group 1 |
| mole | SI unit for amount of a substance |
