Question

Which of the following statements related to lanthanoids is incorrect?

• A. Lanthanoids are silvery white metals.
• B. Samarium shows +2 oxidation state.
• C. Ce⁴⁺ solutions are oxidizing agents.
• D. Colour of lanthanoids is due to d-d transitions.

Hint:

Lanthanoid ion colors arise from f-f transitions within partially filled f-orbitals.

Answer 1

The Correct Option is D

To determine which statement about lanthanoids is incorrect, let's analyze each option:

1. Lanthanoids are silvery white metals: This statement is correct. Lanthanoids, or lanthanides, are generally shiny and have a silvery-white metallic appearance.
2. Samarium shows +2 oxidation state: This statement is correct. Samarium does exhibit a +2 oxidation state, though it more commonly forms a +3 state.
3. Ce⁴⁺ solutions are oxidizing agents: This statement is correct. Cerium in the +4 oxidation state (Ce⁴⁺) is a well-known oxidizing agent due to its ability to be reduced to the more stable Ce³⁺ state.
4. Colour of lanthanoids is due to d-d transitions: This statement is incorrect. The color in lanthanoids arises due to f-f transitions, not d-d transitions, as lanthanoids have electrons filling their 4f orbitals. This is the incorrect statement as lanthanoids do not primarily involve d orbital electron transitions in their coloration.

Hence, the incorrect statement is: Colour of lanthanoids is due to d-d transitions.