Sodium is a soft, silvery-white, highly reactive metal belonging to the alkali metals.
Core Principles & Analysis
Humphry Davy isolated sodium in 1807 by passing electric current through molten sodium hydroxide, one of the first triumphs of electrolysis.
It is a metal soft enough to cut with a knife, reacts violently with water to release hydrogen, and colors flames the intense yellow of its 589 nm emission line.
That yellow light fills sodium-vapor streetlamps, molten sodium cools some fast nuclear reactors, and sodium chloride and hydroxide are pillars of the chemical industry.