Question

In context of the lanthanoids, which of the following statements is not correct?

• A. There is a gradual decrease in the radii of the members with increasing atomic number in the series.
• B. All the members exhibit $+3$ oxidation state.
• C. Because of similar properties the separation of lanthanoids is not easy.
• D. Availability of 4f electrons results in the formation of compounds in $+4$ state for all the members of the series.

Answer 1

Answer: (D)

Availability of 4f electrons results in the formation of compounds in $+4$ state for all the members of the series.

All the members of Lanthanoids exhibit only $+3$ oxidation state in common without any exception and hence option $\left(D\right)$ is not correct.