| A | B |
|---|
| Alkali Metal | Metals with a single valence electron and extremely reactive. |
| Alkaline Earth Metal | Metals with two valence electrons, and are harder than group 1A. |
| Atomic Mass Unit | Used to measure the masses of subatomic particles. |
| Group | A column of elements in the periodic table. |
| Halogens | Nonmetal with seven valence electrons, highly reactive. |
| Metal | Elements that are good conductors of heat and electricity, shiny, ductile, and malleable. |
| Metalloid | Elements with properties that fall between those of metals and nonmetals. |
| Noble Gases | Gases which are colorless, odorless, and extremely unreactive. |
| Nonmetal | Elements that are poor conductors of heat and electricity, dull, brittle, and low melting point. |
| Period | Row in the periodic table of elements. |
| Periodic Law | The pattern of repeating properties displayed by elements in the periodic table. |
| Periodic Table | An arrangement of elements in columns, based on a set of properties that repeat from row to row. |
| Transition Metals | Elements that form a bridge between elements on the left and right sides of the periodic table. |
| Transuranium Elements | Elements with atomic numbers greater than 92. |
| Valence Electron | Electron that is in the highest occupied energy level of an atom |
