1 E.17

[Kaethe Zappacosta 2L]

For each of the following ground-state atoms, predict the type of orbital (1s, 2p, 3d, 4f, etc.) from which an electron will be removed to form the +1 ion: (a) Ge; (b) Mn; (c) Ba; (d) Au

I do not understand this question. I thought the answer would just be wherever the last electron is. If Manganese's last electron is in the 3d orbital, why is the answer for part b 4s?

[Gabriel McDonald 1J]

It's 4s because when the 3d orbital starts to become filled, it is actually at a lower energy state than the 4s orbital. So the electron would get removed from 4s first. Dr. Lavelle showed us that the electron configuration for Scandium would be [Ar]3d¹4s². Similarly, Manganese would be [Ar]3d⁵4s².