Sodium Chemical Properties

Sodium is perhaps the most characteristic alkali metal, reacting violently with water and rapidly with the oxygen in air. It symbol (Na) comes from its Latin name, Natria, whereas its English name is taken from soda which contains it.

As a part of the alkali metal group in the periodic table, sodium is highly reactive and is never found pure in nature. It tarnishes easily and has a low melting point and density. Therefore, sodium is usually stored in mineral oil or kerosene. Chemically, sodium is highly reactive with the halogen family to form ionic salts. For example, sodium is commonly found combined with chloride to form NaCl, known to us as table salt. It has one electron in the outermost electron shell and thus wants to give up one electron to a highly electronegative element. 

Within the alkali metals, sodium is more reactive than lithium but less reactive than potassium. Its ionization energy is higher than potassium but lower than lithium. Sodium is also more metallic than lithium. When exposed to air, sodium oxidizes immediately. When burned, sodium forms sodium peroxide (Na₂O₂) or oxide (NaO₂). If burned in oxygen under pressure, sodium superoxide (NaO₂) is formed. 

Sodium reacts exothermically with water, releasing heat when in contact with water. The chemical equation:

sodium + water → sodium hydroxide + hydrogen gas