Ionization is the process by which an atom or molecule gains or loses electrons, resulting in the formation of charged particles called ions. When an atom loses one or more electrons, it becomes a positively charged ion, or cation. Conversely, when an atom gains electrons, it becomes a negatively charged ion, or anion. This process can occur through various means, including exposure to heat, radiation, or chemical reactions. Ionization is important in many fields, including chemistry, physics, and biology. For example, in mass spectrometry, ionization helps identify and quantify substances by converting them into ions for analysis. Additionally, in plasma physics, ionization is crucial for understanding the behavior of gases at high temperatures, where atoms become ionized and form plasma.