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Chpt 5 vocab
| Term | Definition |
|---|---|
| periodic table | an arrangement of elements in columns, based on a set of properties that repeat from row to row |
| period | each row in the table of elements in the periodic table |
| group | each column on the periodic table |
| periodic law | the pattern of repeating properties |
| atomic mass unit | one twelfth the mass of a carbon-12 atom |
| metals | elements that are good conductors of electric current and heat |
| transition metals | elements that form a bridge between the |
| Non metals | elements that are poor conductors of heat and electric current. |
| Metalloids | elements with properties that fall between those of metals and nonmetals. |
| Valence electron | an electron that is in the highest occupied energy level of an atom. |
| Alkali metals | the elements in group 1A. Have a single valence electron |
| Alkaline earth metals | Elements in group 2A. Have two valence electrons |
| Halogens | elements in group 7A. Have seven valence electrons |
| Noble gases | elements in group 8A. Helium has two valence electrons. Each of the others has eight. |