# What is the electron configuration of iron?

##### 1 Answer

Iron is on the fourth row of the periodic table, sixth column of the transition metals, atomic number

What we have is:

- Its
**core orbitals**are the#1s# ,#2s# ,#2p# 's,#3s# , and#3p# 's. - Its
**valence orbitals**are the#4s# and#3d# 's.

Writing the electron configuration, you really only need the *valence orbitals*, and you can omit the core orbitals by notating it via the **noble gas shortcut**.

So,

Note that the total number of electrons in the neutral atom adds up to the atomic number, so

Finally, the

Therefore, we get:

#color(blue)([Ar]3d^6 4s^2)#

Or:

(note, the original image was wrong. The

The long version is:

#1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2#

Indeed,