# What happens to a neutral nonmetal atom in order for the octet rule to be satisfied?

Jul 5, 2018

It either gains one or more electrons to form a charged monoatomic ion or share one or more pairs of electrons with another atom.

#### Explanation:

The nonmetal atom becomes an ion
Nonmetals can receive electrons from a complete electron transfer to form negatively-charged ions. For example, a neutral chlorine atom might gain one electron to form a chloride ${\text{Cl}}^{-}$ ion:

${\text{Cl"color(white)(l) + color(white)(l) "e"^(-) to "Cl}}^{-}$

The electron added in this process would fill the empty $3 p$ orbital in the chlorine atom to complete the octet.

• $\text{Cl}$: $1 {s}^{2} 2 {s}^{2} 2 {p}^{2} \underline{3 {s}^{\textcolor{n a v y}{2}} 3 {p}^{\textcolor{p u r p \le}{5}}} \textcolor{w h i t e}{l} \textcolor{g r e y}{\text{incomplete valence shell}}$
• ${\text{Cl}}^{-}$: $1 {s}^{2} 2 {s}^{2} 2 {p}^{2} \underline{3 {s}^{\textcolor{n a v y}{2}} 3 {p}^{\textcolor{n a v y}{6}}} \textcolor{w h i t e}{l} \textcolor{g r e y}{\text{extra electron completes the octet}}$

The nonmetal atom forms covalent bonds with other atoms
Alternatively, a nonmetal atom might share one or more pairs of electrons with another atom to achieve an octet. Atomic orbitals of the two atoms "overlap" in a way that valence electrons from one atom fill vacancies in electron orbitals of the other.

For example, a hydrogen atom joins a chlorine atom to form a hydrogen chloride molecule.

The chlorine atom has now attained an octet. (Keep in mind that it takes only two valence electrons for a hydrogen atom to achieve the electron configuration of noble gas helium $\text{H" "e}$, which also contains two electrons. The fact that a hydrogen atom is chemically stable with less than valence eight electrons is an exception to the octet rule).