The most reactive group of metals on the periodic table are the alkali metals. These metals are so reactive that they are not found naturally by themselves; they are found in nature as parts of compounds.
The alkali metals consist of the elements lithium, sodium, potassium, rubidium, cesium and francium. These elements have a single electron in their outermost electron shells. To become more stable, atoms want to keep eight electrons in these outermost shells. The alkali metals like to give away their single electrons in their outermost shells to achieve more stability. Alkali metals tend to be kept isolated or else they react readily with substances in the air. Combining easily with the group of elements called the halogens, alkali metals can form compounds called salts such as sodium chloride, or plain table salt.