The chemical element potassium is a soft,light,silver white metal. it is one of the ALKALI METALS of Group la of the periodic table. its chemical symbol is K {from kalium, the Latinized version of the Arabic word for "alkali"}, its atomic number is 19,and its atomic weight is 39.098. potash, or potassium carbonate {K 2 CO 3 } was well known and had important industrial uses in glass manufacture well before 1700; it was often mistaken, however, for sodium carbonate (Na 2 CO 3 ) and only their decidedly different sources prevented total confusion. Sodium carbonate (soda) is most often found as a mineral, potash was originally derived from the ashes of vegetables materials. Even before the discovery and differentiation of potassium and sodium, potash and sodium carbonate could be identified by their crystal structures like quartz. On Oct. 6, 1807, Sir Humphry Davy connected a piece of solid potash to the poles of battery and causes the release of a new metal at the negative po