| A | B |
|---|
| group | columns on the periodic table |
| period | rows on the periodic table |
| periodic table | an organized chart of the elements in order of atomic number |
| periodic law | the repeating pattern of properties of elements |
| metal | class of elements that are shiny, ductile, malleable and good conductors of heat and electricity |
| nonmetal | class of elements that are dull, brittle and not good conductors |
| metalloid | class of elements that properties of both metals and nonmetals |
| valence electron | electrons in the outer energy shell |
| alkali metal | elements in column 1 of the periodic table |
| alkali Earth metal | elements in column 2 of the periodic table |
| halogen | elements in column 17 of the periodic table |
| noble gas | elements in column 18 of the periodic table |
| transition metal | elements in columns 3-12 of the periodic table |
| reactivity | ability of matter to combine chemically with other substances |
