Sodium is a chemical element with the symbol Na (from Latin natrium) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is the sixth most abundant element in the Earth's crust. Sodium is an essential element for all animals and some plants.

Alkali Metals and Alkaline Earth Metals

The alkali metals (group 1) have very similar properties: they are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. The alkaline earth metals are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.

The alkali metals are a group (column) in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).