Question

Statement I $2^\text{nd}$ and $3^\text{rd}$ transition series exhibit similar radii.
Statement II It is the net result of lanthanoid contraction.

• A. Statement $I$ and Statement $II$ are correct and statement $II$ is the correct explanation of $I$.
• B. Statement $I$ and Statement $II$ are correct but statement $II$ is not the correct explanation of $I$.
• C. Statement $I$ is correct but Statement $II$ is incorrect.
• D. Statement $II$ is correct but Statement $I$ is incorrect.

Answer 1

Answer: (A)

The net result of the lanthanoid contraction is that the elements of second and third $d$-series exhibit similar radii (e.g. $Zr \,160 \,pm, Hf \,159 \,pm$ ) and have very similar physical and chemical properties much more than that expected on the basis of usual family relationship.