Potassium (K)
Potassium (K)
Discovered in 1807, potassium is the seventh most abundant metal. Potassium is not found free in nature, and most minerals that contain it are insoluble, making it difficult to obtain.
The most reactive and electropositive metal, it is the lightest after lithium. Potassium is soft and silvery, can be cut with a knife, rapidly oxidizes in air, and must be stored in a mineral oil such as kerosene. It decomposes in water to produce hydrogen and ignites spontaneously in air. Potassium has 17 isotopes, including one radioactive form.
The greatest demand for potassium is for fertilizers because it is essential for plant growth. Many potassium salts, including the hydroxide, nitrate, carbonate, chloride, chlorate, bromide, iodide, cyanide, sulfate, chromate, and dichromate forms, are also important.