Question

what is the ground state electron configuration of fe^{3+}? the atomic number of fe is z = 26.
ar4s^{2}3d^{6}
ar4s^{2}3d^{8}
ar4s^{2}4d^{8}
ar3d^{5}
ar4d^{6}

Explanation:

Step1: Determine the electron configuration of Fe atom

The atomic number of Fe is 26. The electron configuration of Fe atom is \([Ar]4s^{2}3d^{6}\) (where \([Ar]\) represents the electron configuration of argon: \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\)).

Step2: Remove electrons to form \(Fe^{3 +}\)

When forming \(Fe^{3+}\), we first remove electrons from the highest - energy shell. Electrons are removed from the \(4s\) orbital before the \(3d\) orbital. We remove 2 electrons from the \(4s\) orbital and 1 electron from the \(3d\) orbital.
After removing 3 electrons (\(4s^{2}\) loses 2 electrons and \(3d^{6}\) loses 1 electron), the electron configuration of \(Fe^{3+}\) is \([Ar]3d^{5}\).

Answer:

$$ [Ar]3d^{5} $$