JEE Main · ChemistryHard

$Which of the following statements regarding the crystal field splitting energy of octahedral complexes is correct?$

A. $Δ_{o} increases as the oxidation state of the metal ion decreases.$
B. $Δ_{o} for 4 d series metals is approximately 50% larger than for 3 d series metals.$
C. $Δ_{o} is independent of the nature of the ligand.$
D. $Δ_{o} for tetrahedral complexes is exactly 4/9 of Δ_{o} for octahedral complexes.$

Show correct answer & step-by-step solution

Correct answer: B — $Δ_{o} for 4 d series metals is approximately 50% larger than for 3 d series metals.$

Solution

$Δ_{o} depends on the metal oxidation state, the nature of the ligand, and the principal quantum number of the d-orbitals.$
$For the same ligand and oxidation state, Δ_{o} increases by about 30 - 50% when moving from 3 d to 4 d series.$
$Δ_{t} is approximately 4/9 Δ_{o}, but the statement in D is often considered an approximation rather than an exact physical constant due to ligand geometry differences.$
$Option B is the most accurate description of the periodic trend in crystal field splitting.$
$Hence the answer is (B).$