The chemical element with the symbol K is potassium. Potassium is an essential nutrient for living organisms and plays a crucial role in various biological processes. It is vital for maintaining proper cellular function, nerve conduction, and muscle contraction. In nature, potassium is typically found in compounds, as it is highly reactive with water and air. It is classified as an alkali metal and has an atomic number of 19. Potassium is abundant in many foods, particularly fruits and vegetables, and is important for human health, helping to regulate blood pressure and fluid balance in the body.