Which of the following element, has the highest number of unpaired electrons in it's ground state?

Step-by-step solution

The electronic configurations of the given elements are as aligned & ₂₅ Mn =[ Ar ] 3 d^5 4 s^2 ( 5 unpaired electrons ) & ₂₄ Cr =[ Ar ] 3 d^5 4 s^1 ( 6 unpaired electrons ) & ₂₈ Ni =[ Ar ] 3 d^8 4 s^2 ( 2 unpaired electrons ) & ₂₆ Fe =[ Ar ] 3 d^6 4 s^2 ( 4 unpaired electrons ) & aligned Hence, ₂₄ Cr is having highest number of unpaired electrons i.e., 6 Magnetic moment = 6(6+2) = 48 =6.92 BM (Highest magnetic moment)