Na+, or sodium ion, is a positively charged ion formed when sodium (Na) loses one electron. It is an essential element in many biological processes and plays a crucial role in maintaining fluid balance in the body. Sodium ions are vital for nerve impulse transmission and muscle contraction. In nature, Na+ is commonly found in salt, particularly in sodium chloride (table salt). It is abundant in seawater and is also present in various minerals. The concentration of sodium ions in the body is tightly regulated, as both excess and deficiency can lead to health issues.