# What is the electron configuration of iron 3+?

Jul 14, 2018

Follow the $\text{Aufbau scheme}$...

#### Explanation:

For iron, $Z = 26$..

And so for atomic ion we gots…

${\underbrace{1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{2} 3 {d}^{6}}}_{\text{electronic configuration of atomic iron}}$

And for $F {e}^{2 +}$...we have TWO ELECTRONS LESS.... As is typical for the transition metal series, these are conceived to be $\text{s-shell}$ rather than $\text{d-shell}$.

$F {e}^{2 +} : {\underbrace{1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 3 {d}^{6}}}_{\text{electronic configuration of ferrous ion}}$

You are going to have to read your text for a fuller understanding of why we insist that the $\text{s-shell}$ electrons are removed first...

And so what is the electronic configuration of $\text{ferric ion}$, $F {e}^{3 +}$?