Respuesta :

madsquith04

Answer:

25th electron

Explanation:

the last electron is the valence electron. Assuming it has equal numbers of protons and electrons, then the 25th electron is the valence.

hershbergerm

Answer:   [Ar] 3d5 4s2

Explanation:

Manganese is a transition metal, meaning that it can have more than one valence state. Its electron configuration is [Ar] 3d5 4s2. The two electrons in the 4s orbital are obvious valence electrons, so a valence state of 2+ is possible.