Sodium - n. A common metallic element of the alkali group, in nature
always occuring combined, as in common salt, in albite, etc. It is
isolated as a soft, waxy, white, unstable metal, so readily oxidized
that it combines violently with water, and to be preserved must be kept
under petroleum or some similar liquid. Sodium is used combined in many
salts, in the free state as a reducer, and as a means of obtaining
other metals (as magnesium and aluminium) is an important commercial
product. Symbol Na (Natrium). Atomic weight 23. Specific gravity 0.97.