Concept:According to Crystal Field Theory, ligands approaching a transition metal ion break the degeneracy (equal energy) of its five \(d\)-orbitals, splitting them into lower and higher energy sets.
Solution:- When white light strikes the complex, electrons present in the lower energy \(d\)-orbitals absorb specific wavelengths (energy) and are promoted to the higher energy \(d\)-orbitals.
- This specific movement of electrons exclusively between different \(d\)-orbital energy levels is called a \(d-d\) transition.
- The unabsorbed wavelengths are transmitted, giving the complex its characteristic visible color.
Why other options are incorrect:- Transitions between \(p\) and \(d\) orbitals (or \(s\) to \(p\)) generally require much higher energy (often in the UV region) and are not the primary cause of the typical visible colors in transition metal complexes.
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