Question

The radius of $H{e}^{+}$ ion is $x\mathring{A}$ in its ground state. The radius of $L{i}^{2+}$ ion in the ground state ($\mathring{A}$ ) is:

• A. $\frac{2x}{3}$
• B. $\frac{3x}{2}$
• C. $\frac{2}{3x}$
• D. $\frac{3}{2x}$

Answer 1

The correct option is A $\frac{2x}{3}$

Radius of an orbit $=0.529\times \frac{n^2}{Z}$

$R\propto \frac{1}{Z}$

$\frac{R_1}{R_2}=\frac{Z_2}{Z_1}$

$\frac{x}{R_2}=\frac{3}{2}$

$R_2=\frac{2x}{3}$

Hence, option A is correct.