Answer: -1.2 Delta_o (three electrons each in t 2g , each contributing -0.4 Delta_o).
- A -1.2 Delta_o (three electrons each in t<sub>2g</sub>, each contributing -0.4 Delta_o)
- B Zero, since a d<sup>3</sup> configuration shows no net stabilisation in routine practice
- C +1.2 Delta_o, a positive destabilisation for this configuration overall
- D -0.8 Delta_o, corresponding instead to a d2 configuration in most cases
Correct answer: A. -1.2 Delta_o (three electrons each in t<sub>2g</sub>, each contributing -0.4 Delta_o)
Explanation: In an octahedral field, t<sub>2g</sub> electrons each lower energy by 0.4 Δo; for d<sup>3</sup> (all in t<sub>2g</sub>): CFSE = 3 × (-0.4)Δo = -1.2Δo.
Aqueous solutions of transition metal ions show characteristic colours caused by electrons absorbing visible light to jump between split d-orbitals; the exact colour depends on the metal, its oxidation state, and surrounding ligands.
Concept context
Transition metals (d-block) and lanthanides/actinides (f-block). Known for coloured compounds, variable oxidation states, complex formation, and catalytic properties. Frequently tested in JEE and NEET.