Origin of colour in transition metal complexes

What causes the splitting of d orbitals in octahedral and tetrahedral complexes?

• The presence of unpaired electrons in the d orbitals.
• The temperature of the surrounding environment.
• The interaction of d orbitals with the electric field of surrounding ligands.
• The shape of the metal ion in the complex.

To how many levels of energy do the d orbitals in octahedral complexes spilt in to when ligands approach?

• 5
• 4
• 2
• 3

Which ion does not have any d electrons to promote and therefore does not exhibit colour?

• Fe2+
• Cu2+
• Co2+
• Sc3+

What happens to the light that is not absorbed by a complex ion?

• The light that is not absorbed is transmitted or reflected.
• The light is destroyed and does not exist anymore.
• The light is converted into heat energy.
• The light is completely absorbed by the complex ion.

If a solution absorbs yellow light, what colour will it appear?

• Green
• black

• Red
• Blue

What happens to the colour of a solution when the coordination number changes?

• Higher coordination numbers always result in a darker color.
• The color change is solely due to temperature variations.
• The color remains unchanged regardless of coordination number.
• The color of a solution changes based on the coordination number due to variations in d-orbital splitting.

What are called degenerate orbitals

• Degenerate orbitals are orbitals that have the same energy.
• Orbitals that are unstable and decay.
• Orbitals that are filled with electrons.
• Orbitals that have different shapes.

Why do transition metal ions form coloured complexes?

• They form coloured complexes due to the presence of ligands only.
• Transition metal ions do not form coloured complexes at all.
• Transition metal ions form coloured complexes due to d-d electron transitions that absorb specific wavelengths of light.
• The colour is a result of the metal's atomic number.