JEE Main202125 Feb 2021Morning ShiftChemistryd and f Block ElementsActual
In which of the following pairs, the outermost electronic configuration will be the same?
Options
- ACr + and  Mn 2 +
- BNi 2 +  and  Cu +
- CFe 2 +  and  Co +
- DV 2 +  and  Cr +
Correct answer
A. Cr + and  Mn 2 +
Step-by-step solution
Option 1: Mn + 2 Ar 3   d 5 , Cr + Ar 3   d 5 Cr is expected to have the highest second ionization enthalpy as after removal of 4s electrons, the electrons will be removed from d-orbital. Cr+ have stable half-filled d-orbital with maximum spin multiplicity. Option - 2    Ni + 2 Ar 3   d 8 , Cu + Ar 3   d 10 Option - 3    Fe + 2 Ar 3   d 6 , Co + Ar 3   d 7 4   s 1 Option - 4      V + 2 Ar 3   d 3 , Cr + Ar 3   d 5