An ion is an atom or molecule where the total number of electrons isn't equal to the total number of protons, giving it a net positive or negative electrical charge. An anion (; an-eye-on), from the Greek word ἀνά (ana), meaning 'up', is an ion with more electrons than protons, giving it a net negative charge (since electrons are negatively charged and protons are positively charged). Conversely, a cation (; cat-eye-on), from the Greek word κατά (kata), meani… (More on Ion)