All four complexes given are outer orbital or high spin octahedral complexes. So, d -orbital electrons of central metal ions of the complexes remain unaffected by weak field ligands. So, d -configuration of free Mn+ and coordinated Mn+ will remain same.
1. [
III
Mn
Cl6]3−⟶Mn3+⇒d4,n=4
[∵n= Number of unpaired electrons ] 2. [
III
Fe
F6]3−⟶Fe3+⇒d5,n=5 3. [
III
Co
F6]3−⟶Co3+⇒d6,n=4
4. [
II
Ni
(NH3)6]2+⟶Ni2+⇒d8,n=2
So, complexes 1 and 3 have same number of unpaired electrons (n=4).