# What is the electronic configuration of Mn3+?

The electron configuration for a $\text{Mn"^(3+)}$ ion is $\text{[Ar]3d"^4}$.
Manganese has atomic number 25, meaning its atoms have 25 protons in their nuclei. A neutral manganese atom also has 25 electrons. However, the manganese 3+ ion, $\text{Mn"^(3+)}$, has 22 electrons. This gives it 3 more protons than electrons, which gives it the 3+ charge.
The electron configuration in noble gas shorthand for a neutral Mn atom is $\text{[Ar]3d"^5"4s"^2}$. The electron configuration for a $\text{Mn"^(3+)}$ ion is $\text{[Ar]3d"^4}$. The two 4s valence electrons and one 3d electron is removed.