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Sadie
Ch. 5 Vocablulary
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 |
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 elements on the left and right side of the table |
nonmetals | elements that are poor conductors of heat and electric current |
metalloids | elements with properties that fall between those of metals and nonmetals |
valence electrons | an electron that is in the highest occupied energy level of an atom |
alkali metals | have a single valence electron and are extremely reactive |
alkaline earth metals | have two valence electrons |
halogens | have seven valence electrons |
noble gases | have eight valence electrons, except for helium which has two valence elctrons |