Electron configuration exceptions

[Lily Mohtashami]

Why is the electron configuration for Ni 3d10 and not 3d84s2? I thought only copper and chromium were exceptions?
Also why is Ni2+ 3d8 and not 3d64s2?
Does this mean that vanadium would be 3d5 and not 3d34s2?

[Alexandra Ahlschlager 1L]

I’m pretty sure you’re right about Nickel having the electron configuration [Ar]3d8 4s2, so I’m not too sure why it would be 3d10. Based on the electron configuration of [Ar]3d8 4s2 though, Ni 2+ would be [Ar] 3d8, since you would be removing 2 electrons from the outermost orbital 4s. Also the electron configuration for Vanadium should be [Ar] 3d3 4s2; there shouldn’t be any exception for this element. Hope this helps a little!

[Eliana Witham 2H]

In the notes, the only exceptions are Cr and Cu. But, it makes sense that Ni would want to fill its d orbitals as well. I think you could write Ni's electron configuration both ways. Also, for the Ni2+ cation, the highest energy electrons will be lost first. Therefore, the 4s electrons will be lost before the 3d electron. And for V, I'm not sure the answer but I would go with no because it's not a specified exception.

[Neha Gupta 2A]

Wait yeah I had the same question! In the outline questions it seems to start counting the 3d elements at the beginning of the 4s block which makes it a bit confusing. Is the answer key wrong or is that the actual way to count it?

[YUNALEE]

hi pretty girl
you always want the most stable version so you give the d orbital the 2 electrons it needs to become complete!
luv u

[Mackenzie Van Val 3E]

Ni should be written [Ar] 3d8 4s2 and not [Ar] 3d10. The reason that Cu and Cr are exceptions is that they are only 1 electron away from filling the d-orbital, and thus it makes them more stable to fill up that one electron in the d-orbital rather than the s-orbital. However, I strongly believe that moving 2 electrons from the s-orbital into the d-orbital is incorrect and would not make it more stable, mainly because I know that V is written [Ar] 3d3 4s2 and not as [Ar] 3d5. Furthermore, I think Dr. Lavelle would have told us if there were more exceptions. Also, all my searching online brings Ni up as [Ar] 3d8 4s2. I hope this helps!

[Kandyce Lance 3E]

are we expected to know all the exceptions for the final? or is it fine if we know how to find EC?

[Kandyce Lance 3E]

are we expected to know all the exceptions for the final? or is it fine if we know how to find EC?

Would it be a better idea to try and learn them all anyway?