Question

What is the electron configuration of iron iii?

Answer 1

`1s^2\2s^2\2p^6\3s^2\3p^6\3d^5`

Explanation:

Iron(III) is the ion of iron in its `3+` oxidation state, meaning that it has lost `3` electrons from its valence shell.

The standard electron configuration for an iron atom is:

`1s^2\2s^2\2p^6\3s^2\3p^6\3d^6\4s^2`

Check to see if the total electrons add up to the proton number of the iron, which is `26`.

Now, for iron to lose three electrons, it'll lose its outermost `4s` electrons (both of them), and one of its `3d` electrons. This leaves a configuration of:

`1s^2\2s^2\2p^6\3s^2\3p^6\3d^5`