$\begin{array}{1 1}(a)\;\text{In an octahedral crystal field, the d electrons on a metal ion occupy the }e_g\;\text{ set of orbitals before they occupy the }t_{2g}\;\text{set of orbitals}\\(b)\;\text{Diamagnetic metal ions cannot have an odd number of electrons}\\(c)\;\text{Low spin complexes can be paramagnetic}\\(d)\;\text{In high spin octahedral complexes,}  \Delta_{oct}\text{ is less than the electron pairing energy, and is relatively very small}\end{array}$
