Question

For $L{i}^{+2},r_2:r_5$ will be :

• A. 9 : 25
• B. 4 : 25
• C. 25 : 4
• D. 25 : 9

Answer 1

Answer: (B)

4 : 25

For $L{i}^{+2},r_2:r_5$ will be 4 : 25.
The radius is proportional to $\frac{n^2}{Z}$.
For $L{i}^{2+}$
$r_2\propto \frac{2^2}{3}$

$r_2\propto \frac{4}{3}$ ......(1)

$r_5\propto \frac{5^2}{3}$

$r_5\propto \frac{25}{3}$......(2)
From (1) and (2)
$\frac{r_2}{r_5}=\frac{4}{3}\times \frac{3}{25}=\frac{4}{25}$