Potassium

Potassium is a chemical element with the symbol K and atomic number 19. It belongs to the group of alkali metals, which are soft, highly reactive metals. Pure potassium is a silvery solid that is soft enough to be cut with a knife and is extremely light.

It does not occur in nature in pure form, since it reacts rapidly with air and water. It is found in salts and mineral ores, and is also present in the sea. In the human body, potassium is an essential mineral for the functioning of cells.

Chemical properties

Potassium has one electron in its outermost shell, which is easily lost. For this reason, it readily forms the K+ ion when it reacts. When placed in water, it releases hydrogen gas and considerable heat, usually catching fire. It is therefore stored in oil or in an inert gas.

Role in life

The potassium ion plays a major role in maintaining the balance within cells. It and sodium work together to regulate the electrical charge of the cell membrane, which affects the transmission of nerve signals and muscle contraction, including that of the heart. Foods rich in potassium include bananas, dates, chicken, and leafy vegetables.

Industrial and agricultural use

The largest portion of potassium extracted is used as a fertilizer. Potash is the general term for potassium salts used in fertilization; it is one of the three essential minerals that plants require, along with nitrogen and phosphorus. Other uses include the manufacture of soap, glass, and various chemicals.

History of discovery

Potassium was first isolated in pure form in the early nineteenth century through the electrolysis of potash. The name 'potassium' derives from the word 'potash', which referred to the residue of ashes left after burning wood; the symbol K comes from the Latin name 'kalium'.