Alkali & Alkaline-Earth Metals (Periodic Table of the Elements)

Scientists categorize the chemical elements as metals, nonmetals, and metalloids largely based on the elements' abilities to conduct electricity at normal temperatures and pressures, but there are other distinctions taken into account when classifying the elements in the periodic table. The alkali metals, for example, are metals, but have such special properties that they are given their own classification. The same is true for the alkaline earths.