# What is the electron configuration for a chloride ion?

Dec 31, 2015

$1 {\text{s"^2 2"s"^2 2"p"^6 3"s"^2 3"p}}^{6}$

OR

${\text{[Ne]" 3"s"^2 3"p}}^{6}$

#### Explanation:

The electron configuration of a chlorine atom ($\text{Cl}$) is as follows:

$1 {\text{s"^2 2"s"^2 2"p"^6 3"s"^2 3"p}}^{5}$

But a chlorine ion (${\text{Cl}}^{-}$) has acquired a $\text{(1)-}$ charge as a result of gaining 1 electron. Thus, its electron configuration is:

$1 {\text{s"^2 2"s"^2 2"p"^6 3"s"^2 3"p}}^{6}$

This may also be expressed as:

${\text{[Ne]" 3"s"^2 3"p}}^{6}$