Potassium is a chemical element, having the chemical symbol K. Its atomic number (the number of protons) is 19. It has a standard atomic weight of 39.0983 g•mol −1, and is typically found as a solid in its elemental form.
Potassium is considered to be a member of the "alkali metal" class of element. At a pressure of 101.325 kPa, it has a boiling point of 769 °C, and a melting point of 65.5 °C. It is a silvery-white, reactive metal. Potassium reacts violently with water, producing hydrogen.
Potassium in its cation form (K+) performs many different functions within the human body. K+ is essential for cellular function and maintaining homeostasis through action potentials.
Potassium is a vital ion in cellular communication via the action potential.