Q12 / 75 · JEE Main 2026 (05 April Shift 1) · Chemistry
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.
In the light of the above statements, choose the correct answer from the options given below
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.
In the light of the above statements, choose the correct answer from the options given below
- Correct answerABoth Statement I and Statement II are correct
- BBoth Statement I and Statement II are incorrect
- CStatement I is correct but Statement II is incorrect
- DStatement I is incorrect but Statement II is correct
Solution
In an octahedral crystal field, the five degenerate d-orbitals split into two sets: a lower energy $t_{2g}$ set and a higher energy $e_g$ set.
The energy of the $t_{2g}$ orbitals is lowered by $0.4\Delta_o$ (stabilization of $-0.4\Delta_o$) and the energy of the $e_g$ orbitals is raised by $0.6\Delta_o$ (destabilization of $+0.6\Delta_o$) 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
The energy of the $t_{2g}$ orbitals is lowered by $0.4\Delta_o$ (stabilization of $-0.4\Delta_o$) and the energy of the $e_g$ orbitals is raised by $0.6\Delta_o$ (destabilization of $+0.6\Delta_o$) 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
Hence, the correct answer is option: 'A'.