Potassium has 20 neutrons, 19 protons and 19 electrons. It has the chemical symbol K and is an alkali metal. It has a low density of 0.89 grams per cubic centimeter and an atomic weight of 39.09 grams per mole.
The Earth's crust contains approximately 2.1 percent potassium. Many ores including sylvite, carnallite and polyhalitedo contain potassium.
Potassium is a highly reactive element that reacts with oxygen and water. Many compounds of potassium have diverse uses in different industries. Potassium carbonate is useful for making glass and soaps. Potassium chloride is a common potassium compound used in agriculture as a fertilizer.