Multiple choice Which of the following ions have electronic configuration [Ar] 3d5? Mn2+ and Fe2+ Sc3+ and Fe3+ Mn2+ and Ni3+ Cr3+ and Fe3+ Mn2+ and Fe3+ Reveal answer Fill a bubble to check yourself E Correct answer Explanation Mn2+ (23 e-): [Ar] 3d5 Fe3+(23 e-): [Ar] 3d5