Elements in the periodic table that have specific properties such as conductivity of electric and heat are classified as metals. Metals tend to lose electrons and therefore have a positive charge (cation).

Elements in the periodic table that do not share the properties that characterize metals, are classified as nonmetals. Nonmetals tend to have an affinity for electrons and therefore, possess a negative charge 
(anion). All nonmetals except for Hydrogen reside in the upper right of the periodic table. Hydrogen resides in the upper left.