In an octahedral crystal field, the five degenerate d-orbitals split into two sets: a lower energy t2g set and a higher energy eg set.
The energy of the t2g orbitals is lowered by 0.4Δo (stabilization of −0.4Δo) and the energy of the eg orbitals is raised by 0.6Δo (destabilization of +0.6Δo) relative to the barycenter. Hence, Statement I is correct.
In the free atomic or ionic state, all five d-orbitals of a transition metal are degenerate (have the same energy). When ligands approach the central metal ion to form a complex, the spherically symmetrical field is disrupted, which destroys the degeneracy of the d-orbitals and causes them to split. Hence, Statement II is correct.
Both Statement I and Statement II are correct.
Answer: Both Statement I and Statement II are correct