Naatrium

Naatrium, commonly known as sodium, is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery‑white alkali metal that is highly reactive, especially with water. In pure form it can be cut with a knife and has a relatively low density and melting point for a metal, melting at 97.72 degrees Celsius and boiling at 883 degrees Celsius.

Naatrium is the third most abundant element in the Earth's crust and is not found free in nature; it occurs primarily in compounds such as sodium chloride (table salt), soda ash, and natrium minerals. Commercial production is achieved mainly by electrolysis of molten sodium chloride (the Downs process), with historical methods related to chlorine evolution. The metal is highly reactive and is typically stored under oil or in an inert atmosphere to prevent contact with air and moisture.

Naatrium and its compounds have widespread uses. Sodium chloride is essential for food and preservation. Sodium hydroxide and sodium carbonate are key industrial chemicals. Sodium compounds are used in glass production, chemical synthesis, and as reducing agents in metallurgy. Sodium vapor lamps, emitting a characteristic yellow light, are used for street lighting and some industrial applications. In certain nuclear reactors, sodium metal is used as a heat-transfer medium.

Sodium is an essential electrolyte in biology, necessary for nerve function, muscle contraction, and fluid balance. It reacts vigorously with water and air, so handling requires safety precautions to prevent ignition or chemical burns.

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