Strontium is the fourth element in Group 2 of the periodic table, a group of elements known as the alkaline earth metals. It has an atomic number of 38, an atomic mass of 87.62, and a chemical symbol of Sr.

Properties

Strontium is a silvery white metal that combines with oxygen of the air to form a thin film of strontium oxide (SrO). The film gives the metal a yellowish hue and protects it from further oxidation. Strontium has a melting point of 1,395°F (757°C), a boiling point of 2,491°F (1,366°C), and a density of 2.6 grams per cubic centimeter.

Strontium is a very active element that is normally kept under kerosene, mineral oil, or some other organic liquid to keep it from reacting with oxygen in the air. In a finely divided form, the metal may catch fire spontaneously and burn vigorously. Strontium is active enough to...