Question

Identify the incorrect statement among the following.

• A. There is a decrease in the radii of the atoms or ions as one proceeds from La or Lu
• B. Lanthanide contraction is the accumulation of successive shrinkages
• C. As a result of lanthanide contraction, the properties of 4d series of the transition elements have no similarities with the 5d series of elements
• D. Shielding power of 4f electrons is quite weak

Answer 1

Answer: (C)

The regular decrease in the radii of lanthanide ions from $L{a}^{3+}$ to$L{u}^{3+}$ is known as lanthanides contraction.
It is due to the greater effect of the increased nuclear charge than that of screening effect (shielding effect).
As a result of lanthanide contraction, the atomic radii of element of $4d$ and $5d$ come close, so the properties of $4d$ and $5d$-transition element shows the similarities