Potassium is a highly reactive metal in Group 1 of the periodic table. Potassium like the other alkali metals needs to be stored in oil to prevent reactions with the moisture and oxygen in the air, it can also be cut with a knife and reacts violently with water to produce a lilac flame. Potassium was first isolated from Potash (the ash of plants) from which its name is given. Georg Ernst Stahl conducted the first experiments on Potash in 1702 but it was not until 1807 that Sir Humphry Davy isolated potassium from Potassium Hydroxide, a common solution containing Potassium, using a voltaic pile. Being in Group 1 and having one valence electron, Potassium likes to exist in compounds and is not found naturally in the earths crust. It is commonly found in sea water and in minerals in the earth’s crust. Potassium’s main use is in fertiliser as a source of potassium for plants, it also has uses in solutions such as Potassium Hydroxide as a strong base for neutralising acids. It is also the ninth most abundant element in the human body where it is used in membranes and hormone secretion. In the human diet it is commonly found in fruits such as Apricots and Bananas as well as milk and soya. It is located in Group 1 as an Alkali metal which is very reactive with water . It has a melting point of 63.5°c and a boiling point of 759°c.
Sir Humphrey Davy