Multiple choice Which of the following transition metal ions have four unpaired electrons? Cr3+ V3+ Fe2+ Co3+ Only 1 and 2 Only 1 and 3 Only 2 and 3 Only 2 and 4 Only 3 and 4 Reveal answer Fill a bubble to check yourself E Correct answer Explanation It is correct. Fe2+: [Ar] 3d6; 4 unpaired electrons Co3+: [Ar] 3d6; 4 unpaired electrons