An ion is defined as an atom or molecule that possesses a full positive or negative charge due to an imbalance in the number of electrons and protons. When an atom gains electrons, it becomes negatively charged and is termed an anion. Conversely, when an atom loses electrons, it becomes positively charged and is referred to as a cation.
For example, a common ion is sodium (Na+). Sodium, when it loses one electron, becomes a sodium ion with a positive charge. This process is essential in various chemical reactions and plays a crucial role in forming ionic compounds, such as sodium chloride (table salt), where Na+ pairs with chloride ions (Cl−) to create a stable structure.