Nonmetals generally form anions rather than cations. An ion is an atom or a group of atoms that carries an electric charge. Cations are positively charged ions, while anions are negatively charged ions.
Nonmetals tend to have higher electronegativity values, meaning they have a greater tendency to attract electrons. When nonmetals gain electrons, they achieve a stable electron configuration similar to that of the nearest noble gas. This process results in the formation of negatively charged ions or anions.
For example, chlorine (a nonmetal) has seven valence electrons. By gaining one electron, it achieves a stable configuration of eight electrons, like the noble gas argon. The resulting chloride ion (Cl-) carries a single negative charge.
However, it's important to note that there are exceptions to this general trend. Some nonmetals, such as hydrogen and the metalloids (elements with properties between metals and nonmetals), can form cations under certain conditions. Additionally, nonmetals can also participate in covalent bonding, where they share electrons with other nonmetals rather than gaining or losing them to form ions.