Potassium is a chemical element. It has the symbol K (Arabic: al qalja → Latin: kalium) and atomic number 19. The name "potassium" comes from the word "potash", as potassium was first isolated from potash. Potassium is a soft silvery-white metallic alkali metal that occurs naturally bound to other elements in seawater and many minerals. It oxidizes rapidly in air and is very reactive, especially towards water. In many respects, potassium and sodium are chemically similar, although organisms in general, and animal cells in particular, treat them very differently.
||Melting point /°C
||Boiling point /°C
|No. of naturally occurring isotopes
||*(radioactive 4°K t1/2 1.27 x 109 y)
|Temperature (oC) @Vap. Pressure
||Alloys with refractory metals; rapid Evaporation suggested. Spits in EB.