Sodium comprises one half of the compound sodium chloride, better known as common or table salt. Sodium is the 11th element on the periodic table, and takes the form of a silvery soft metal at standard pressure and temperature.
This element burns yellow and carries several warnings when handling. It is highly reactive with water, explosively creating a great deal of heat, flammable hydrogen gas and the caustic compound sodium hydroxide upon contact. Powdered sodium can combust spontaneously in oxygen-rich environments. It is the sixth most abundant element in the Earth's crust, often found naturally as the compound sodium chloride in crystalline rock salt formations.