Potassium ion is a chemical species that has a positive charge and is in the category of cations. It is a vital mineral that helps to maintain the balance of fluids in the body, regulate the heartbeat, and support the functioning of nerves and muscles. Potassium ions are commonly referred to as K+ or potassion, depending on the context. Other synonyms for potassium ion include kalium, atomic number 19, metal ion, and mineral cation. These synonyms can be used interchangeably with potassium ion, depending on the context in which they are used. Overall potassium ions play an essential role in many biological processes and are vital for maintaining a healthy body.