Do exceptions apply to ions?

[Ben Apsley]

Do the exceptions to electron configuration rules (like copper or putting 3d before a) apply to ions? For example, if you had an ion with 3d9 4s2, would this become 3d10 4s1?

[Joshua Han]

No it wouldn’t because in these exceptions it occurs in the d block meaning the only type of ion occurred are cations. Cations will always remove electrons from the orbital with most energy which in that case is always gonna be the 4s orbital, therefore that situation can not occur so the exceptions won’t occur.