# Electron Config. for Sg+2: Explained

## Homework Statement

For Sg+2 what is the electron configuration.

## The Attempt at a Solution

My immediate response would be [Rn] 7s2, 5f14, 6d2
but the answer is [Rn] is 5f14 6d4

Can someone explain this to me?

If the answer is correct, this means the math works out that the 7s-shell valance orbitals are at an actually higher energy than the 6d or 5f orbitals. I think this might be the answer, but I'm not familiar enough with calculations to say for sure.

Per analogy with transition metals I would expect 7s electrons to be lost first. Why makes you think it should be 6d?

I suppose I don't fully understand electron orbitals concept. Upon a little more brain digging, we remove heighest energy level electrons first?

Yes, the electrons in an atom in its ground state are arranged in the orbitals from lowest energy to highest. If the 7s orbitals happen to be at a higher energy than the 6d or 5f orbitals, then the 6d and 5f orbitals would fill up before the 6s orbital fills up.