Question

Given below are two statements:
Statement I: Each electron in \(e_g\) orbitals destabilizes the orbitals by \(+0.6 \Delta_o\) and each electron in the \(t_{2g}\) orbitals stabilizes the orbitals by \(-0.4 \Delta_o\) in an octahedral field on the basis of crystal field theory.
Statement II: All the d-orbitals of the transition metals have the same energy in their free atomic state but when a complex is formed the ligands destroy the degeneracy of these orbitals on the basis of crystal field theory.

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question involves the fundamental principles of Crystal Field Theory (CFT) regarding d-orbital splitting in octahedral complexes.
Step 2: Detailed Explanation:
Statement I: In an octahedral field, the five d-orbitals split into two sets: lower energy \(t_{2g}\) (3 orbitals) and higher energy \(e_g\) (2 orbitals). The energy center (barycenter) is maintained. The \(t_{2g}\) set is lowered by \(0.4 \Delta_o\) (stabilization) and the \(e_g\) set is raised by \(0.6 \Delta_o\) (destabilization) per electron. Correct.
Statement II: In a free atom, all five d-orbitals are degenerate (same energy). When ligands approach, an electrostatic field is created. If the field is non-spherical (as in octahedral or tetrahedral geometry), it causes the d-orbitals to split into different energy levels, destroying the degeneracy. Correct.
Step 3: Final Answer:
Both statements are correct.