The element potassium is a metal and it belongs to Group 1, which consists of the alkali metals. Potassium is soft and silver-white in appearance. Its chemical symbol is K, and it has an atomic number of 19.
A characteristic of alkali metals is that they are very reactive. Potassium is an active metal that also has physical properties, such as a melting point of 146.08 degrees Fahrenheit (63.38 degrees Celsius) and a density of 0.89 grams per cubic centimeters. Its density is lower than water, which is 1.00 grams per cubic centimeters.
In ancient times, humans knew how to recover potash, a compound of potassium that formed through the burning of wood. Another name for potash obtained from wood ashes is potassium carbonate. Potassium is also present in soda ash.
Potassium is not present in pure form in nature. Many minerals, such as sylvite and polyhalite, contain this element. In 1807, Humphry Davy used the electrolysis process to isolate and recover potassium from potash.
The applications of potassium include as a heat medium for some nuclear reactors, as a nutrient in fertilizers and fireworks in the form of potassium nitrate.