How can we deduce which complex ion will have greater splitting of the 3d orbital if they have the same number of electrons? (5)

The complex ion with the higher nuclear charge on the metal ion = bec it causes the ligands to be pulled in closer to the metal ion = greater repulsion bw the ligand electrons and the d electrons of the metal ion = greater splitting of the d orbitals EG: [Mn(H2O)6]2+ and [Fe(H2O)6]3+ both have 5 3d electrons = greater splitting in the Fe ion bec it has 26+