The element with the chemical symbol Na is sodium. Sodium is an alkali metal, situated in group 1 of the periodic table. It is highly reactive and is not found in its free form in nature due to its reactivity with water and air. Sodium is essential for many biological processes and plays a vital role in the human body, particularly in maintaining fluid balance and transmitting nerve impulses. It is commonly found in table salt (sodium chloride) and is widely used in various chemical reactions and industrial applications.