A cation is a positively charged ion that forms when an atom loses one or more electrons. This loss of negatively charged electrons results in an overall positive charge, making cations important in various chemical reactions and processes. Common examples of cations include sodium Na+, potassium K+, and calcium Ca2+. Cations play a crucial role in the formation of ionic compounds, where they bond with negatively charged ions called anions. This interaction helps create stable structures, such as table salt NaCl, which consists of sodium cations and chloride anions. Cations are also essential in biological systems, influencing functions like nerve transmission and muscle contraction.