Sodium comes from the fusion of two carbon atoms in stars that are at least three times as massive as the sun, even though the sun itself has a fair amount of sodium. On Earth, sodium is found in salt, natron and minerals such as zeolite.
Sodium, a very reactive alkali metal, is never found in its free state. It has an atomic number of 11 and is part of Group 1 on the periodic table. Pure metallic sodium is used as a reducing agent in the chemical industry. Sodium vapor is used in street lights. As a liquid, sodium is also used as a coolant in nuclear reactors.