# How will the Fe reach noble gas configuration? The problem I have is that, for example in FeO, iron may keep its 8 valence electrons, but it still won't reach noble gas configuration nor electron octet.

May 2, 2015

Iron has the electron configuration:

$\left[A r\right] 3 {d}^{6} 4 {s}^{2}$

When it forms FeO the 2 outer 4s electrons are lost to form $F {e}^{2 +}$ which is:

$\left[A r\right] 3 {d}^{6}$

Iron has 8 valence electrons and its most common oxidation states are +2 and +3. In non of these does it attain a noble gas configuration.

This is because is because the octet "rule" is a rule and not a law so is not applicable in all cases. In fact it only applies to a limited number of elements.