Ions are formed when a neutral atom or molecule gains or loses one or more electrons, creating an imbalance between the number of protons and electrons. Atoms that lose electrons become positively charged cations (like a sodium atom forming a sodium ion, Na⁺), while atoms that gain electrons become negatively charged anions (like a chlorine atom forming a chloride ion, Cl⁻). How Atoms Become Ions Gain or Loss of Electrons: The most common way for ions to form is through the transfer of electrons