# What is electron configuration of fluoride ion?

Dec 5, 2016

${F}^{-} : 1 {s}^{2} 2 {s}^{2} 2 {p}^{6}$

alternatively:
${F}^{-} : \left[N e\right]$

#### Explanation:

Elemental Fluorine has an electron configuration of $1 {s}^{2} 2 {s}^{2} 2 {p}^{5}$ and needs 1 more electron to complete its $2 p$ orbital which it will acquire in formation of the fluoride ion.

Thus it gains an electron when forming the fluoride ion, and becomes isoelectronic to neon.