The alkali metals are Group 1 or Group 1A metals. These metals are lithium (LI, number 2), sodium (Na, number 11), potassium (K, number 19), rubidium (Rb, number 37), caesium (Cs, number 55), and francium (Fr, number 87). Alkali metals can be identified by the single electron in the outer ring of an atom of the metal. Alkali metals are soft, shiny, and react by giving off extremely heated hydrogen gas when placed in water. Alkali metals are not found in isolation in nature but are important in many common compounds. Sodium and potassium are very common elements found in many compounds; the other metals are much less common.