Potassium<\/a> is a chemical element with the symbol K and Atomic-Number<\/a> 19. Classified as an Alkali-Metal<\/a>, it is a soft, silvery-white solid that oxidizes rapidly in air and reacts vigorously with water. It was first isolated in 1807 by Humphry-Davy<\/a> from Caustic-Potash<\/a>. This element is the seventh most abundant in the Earth's crust. Detailed chemical properties can be explored via the Royal Society of Chemistry<\/a>.<\/p> Biologically, Potassium<\/a> is an essential Mineral<\/a> and Electrolyte<\/a> required for the function of all living cells. It plays a critical role in Nerve-Transmission<\/a>, Muscle-Contraction<\/a>, and the maintenance of Fluid-Balance<\/a>. High dietary intake is associated with a lower risk of Stroke<\/a> and Hypertension<\/a>, according to research cited by the World Health Organization<\/a>. Major food sources include Potatoes<\/a>, Bananas<\/a>, and Spinach<\/a>.<\/p>