The Correct Answer for in the ground-state electron configuration of fe3+, how many unpaired electrons are present?
Iron has 5 unpaired electrons in Fe⁺³ state.
Iron having atomic number 26 has following electronic configuration in neutral state.
Fe = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁶
When Iron looses three electrons it attains +3 charge with following electronic configuration.
Fe⁺³ = 1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁵
The five electrons in d-orbital exist in unpaired form as,
3(dz)¹, 3d(xz)¹, 3d(yz)¹, 3d(xy)¹, 3(dx²-y²)¹