Configuration of Fe

[Jonghwee Park 1K]

For iron (Fe), is the electron configuration 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^6, 4s^2. We touched on it during discussion, but I forgot what and more importantly how we should write these configurations once the d-orbital gets involved. Thanks!

[Garrett Dahn 1I]

That is the correct electron configuration, yes. That 3d comes before 4s because the n energy level of 3d (n = 3) is lower than the n energy level of 4s (n = 4), and according to the Aufbau principle, electrons will occupy lower energy levels before they occupy higher ones.

[kendallbottrell]

Remember that it is very likely you will be able to use the "shorthand" - [Ar] 3d^6 4s^2. If it helps, a TA suggested writing it out the way you see it and then rearranging the the d orbital before the s orbital.