| A | B |
|---|
| group | each column on the periodic table |
| period | each row on the periodic table |
| metals | elements that are good conductors of electric current and heat |
| atomic mass unit (amu) | one twelfth the mass of a carbon-12 atom |
| metalloids | elements with properties tha tfall between those of metals and nonmetals |
| nonmetals | elements that are poor conductors of heat and electric current |
| transition metals | elements that form a bridge between the elements on the left and right sides of the periodic table |
| valence electron | electron that is in the highest occupied energy level of an atom |
| alkali metals | elements in Group 1A |
