Question

The radius of $L{a}^{+3}(Z=57)$ is $1.06A^{\circ }$. Which of the following given values is closest to the radius of $L{u}^{2+}(Z=71)$:

• A. $1.60A^{\circ }$
• B. $1.40A^{\circ }$
• C. $1.06A^{\circ }$
• D. $0.85A^{\circ }$

Answer 1

The correct option is D $0.85A^{\circ }$

Due to poor shielding effect of $4f$ electrons effective nuclear increases with increment in f electrons. Size of f block elements decreases with increase in atomic number as there is an effective nuclear charge. Therefore size of $L{u}^{+2}$ < $L{a}^{+3}$

Hence, the correct option is $\text{D}$