The difference between potassium and sodium was not discovered until the 18th century. "Vegetable alkali" also known as potassium carbonate came from the earth. "Mineral alkali" also known as sodium carbonate came from wood ashes. Early chemists did not recognise that these were two different chemical compounds.
Sir Humphry Davy discovered potassium in 1807 in England, by isolating it using electrolysis. Potassium was the first metal to be isolated by using electrolysis. The name potassium originated from the English word "potash" meaning pot ashes and the Arabic word "qali" meaning alkali. This was because potassium was originally obtained by soaking wood ashes in water and then evaporating the mixture in an iron pot. The origin of the elements symbol “K” comes from the Latin word "kalium" meaning potassium. Potassium used to be called kalium, so the element symbol is 'K'.
Potassium is an "Alkali Metal," and a solid element. Alkali Metals are very reactive metals that do not occur freely in nature. They are are soft, malleable, and good conductors of heat and electricity. It is the 19th element on the periodic table, and located in group 1, period 4.
Potassium is very reactive, and is never found free in nature. It is the eighth most abundant element on earth, and makes up about 2.1% of the earth's crust. Potassium is obtained from the minerals sylvite, carnallite, langbeinite, alunite, and polyhalite. These minerals are mainly found in sea beds and ancient lakes. Potassium is also found in caustic potash. Caustic potash is mainly mined in Germany, New Mexico, California and Utah. Annual world production of potassium is about 200 tons. Primary mining areas for Potassium are Germany, Spain, Canada, USA and Italy.
When potassium is pure it is a soft, waxy metal. It can easily be cut with a knife. Potassium is a soft, silver-white, highly explosive and reactive metallic element. Potassium only occurs in nature in compounds. It oxidizes white in the air and reacts violently in water, and produces potassium hydroxide and hydrogen gas. This reaction releases enough heat to ignite the hydrogen gas, which will explode in the presence of oxygen. Common fire extinguishers including oxygen will not put out potassium fires, and in many cases worsen the fire. Dry fire extinguishers must be used in order to deprive it of oxygen and cool the potassium metal. Potassium is made during explosive oxygen burning in supernovae. Most of the potassium atoms in the universe were made in the final moments of giant stars as they exploded in the supernovae. Potassium is created in the oxygen burning shell of stars as they explode, in a process known as nuclear fusion. Potassium’s melting point is very low for a metal. It will melt over the flame of...