n. Symbol K
A soft, silver-white, extremely reactive element that is an alkali metal, is essential to plant and animal cell functions, and occurs in nature only in compounds. It can be obtained by electrolysis of its hydroxide and is found in, or converted to, a wide variety of salts used especially in fertilizers and soaps. Atomic number 19; atomic weight 39.098; melting point 63.5°C; boiling point 759°C; specific gravity 0.86; valence 1. See Periodic Table.
[From earlier potass, potash (from which it was first obtained), from French potasse, from Dutch potas : pot, pot (from Middle Dutch; akin to Old English pott) + as, ash (from Middle Dutch asche; see as- in the Appendix of Indo-European roots).]
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