Sodium is a soft, silvery-white alkali metal represented by the symbol Na. It is highly reactive and is never found in its free state in nature. Sodium reacts vigorously with water and must be stored in oil.

Sodium is an important part of common salt (NaCl). In the human body, sodium helps in maintaining fluid balance and proper functioning of nerves and muscles. Sodium compounds are used in food preservation, soap making, and street lighting.