The symbol for the chemical element sodium is "Na." This symbol comes from the Latin word "natrium," which is derived from the Greek word "natron," referring to sodium carbonate. Sodium is an essential element in many chemical processes and is classified as an alkali metal found in Group 1 of the periodic table. It is highly reactive, especially with water, and is typically found in nature as part of compounds, such as table salt (sodium chloride). Sodium plays a vital role in biological systems, including nerve function and fluid balance in living organisms.