Wenow call it soda, and from this word the element sodium takes its name. The chemical symbol for sodium is Na, after the word natron . Sodium is the seventh most common element in the Universe and comprises one-thirtieth of the Earth's crust. On Earth its compounds give sea water its salty taste. Itwas also used as a cleaning agent, and for making glass and pottery.
Sodium is also vital to regulating many body processes.
For all these reasons, sodium remains one of the most widely used elements. All in all, we consume about a hundred million tonnes of sodium compounds every year. But although you can see sodium in many compounds, it is rare to see the soft, silvery-coloured metal that is pure sodium because it reacts violently in air and water. In nature, sodium is always found combined with other elements. Potassium Potassium, the twentieth most common element in the Universe and the seventh most common on Earth, is a lightweight, soft, silvery-coloured metal, whose name comes from the word potash .