Sodium (Na), is a chemical element of Group 1 (Ia) of the periodic table (the alkali metal group). Sodium is a very soft, silvery-white metal. Sodium is the most common alkali metal and the sixth most abundant element on Earth, comprising 2.8 percent of the Earth's crust. It occurs abundantly in nature in compounds, especially common salt—sodium chloride (NaCl)—which forms the mineral halite and comprises about 80 percent of the dissolved constituents of seawater.

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