The alkaline earth metals (earth metal comes from alchemy, which was used to describe metals that resisted fire -- the oxides of the alkaline earth metals are not affected by fire) are a chemical series.

They are the elements in Group 2 of the Periodic Table: Beryllium, Magnesium, Calcium, Strontium, Barium and Radium (not always considered due to its very short half-life).

The alkaline earth metals are silvery colored, soft, low density metals, which react readily with halogens to form ionic salts, and with water, though not as rapidly as the alkali metals, to form strongly alkaline (basic) hydroxides. For example, where sodium and potassium react with water at room temperature, magnesium reacts only with steam and calcium with hot water. These elements all have two electrons in their outermost shell, so the energetically preferred state of achieving a filled electron shell is to lose two electrons to form a doubly charged positive ion.