Ions are charged particles that form when atoms gain or lose electrons. When an atom loses one or more electrons, it becomes a positively charged ion, known as a cation. Conversely, when an atom gains electrons, it becomes a negatively charged ion, called an anion. Ions play a crucial role in various chemical reactions and are essential for the functioning of living organisms. For example, sodium and potassium ions are vital for nerve signal transmission in the human body. Additionally, ions are involved in the formation of salts and other compounds, influencing properties like solubility and conductivity.