Electron Configuration for Fe 3+

[Daniel-1G]

Could someone explain to me why the electron configuration for Fe 3+ is not the same as Vanadium of [Ar]3d3 4s2 and is instead [Ar]3d5? Is this just an exception like copper that we should have memorized?

[Alyssa_Wieand_2G]

When I work this out, I first write out the structure for the ground state configuration which would be [Ar] 3d^6 4s^2 and then I just take electrons out in the order that is written so Fe3+ would be [Ar]3d^5 since the 4s block has slightly lower energy and they are filled first. Hope this helps!

[Rachel Wile 2D]

You take electrons out of the 4s orbital, before you take them out of the 3d orbital, because it is lower energy to have them in the 3d orbital in comparison to the 4s.

[Tyler_Honrada_1L]

How can you tell if the orbital has a lower energy level? Is it just something we have to memorize. I've heard Dr. Lavelle say this many times in lecture so is it just like something that's given?

[Helen_Onuffer_1A]

I think that once you start filling the 3d orbital, it becomes lower energy than the 4s orbital. It's probably more complicated than that, but we haven't really learned all the details yet.

[Jennah Muhammad 1H]

on exams will we be required to find the ground state electron configuration using the noble gas notation? or will it require us to just write the general electron configuration