Sodium is a soft, silvery-white, highly reactive metal belonging to the alkali metal group in the periodic table. It has the atomic number 11 and symbol Na, derived from the Latin word Natrium. Sodium is essential for life, playing a crucial role in nerve function, fluid balance, and muscle contraction in the human body. It is commonly found in nature as part of compounds like sodium chloride (table salt), baking soda, and soda ash. Due to its high reactivity, sodium does not occur freely in nature but is extracted from minerals like halite. It reacts vigorously with water, producing hydrogen gas and heat. Industrially, sodium is used in metallurgy, soap making, glass manufacturing, and as a coolant in nuclear reactors. While necessary for health in small amounts, excessive sodium intake can lead to hypertension and other health issues, making moderation important in diet and consumption.