Question

The radius of the hydrogen atom in the ground state is $0.53\mathring{A}$, the radius of $L{i}^{2+}$ in a similar state is____.

• A. $1.06\mathring{A}$
• B. $0.265\mathring{A}$
• C. $0.175\mathring{A}$
• D. $0.53\mathring{A}$

Answer 1

The correct option is C $0.175\mathring{A}$

Radius of hydrogen like particle $r_n=a_0\frac{n^2}{2}$

$0.530\mathring{A}=a_0\frac{1^2}{1}$

$a_0=0.53\mathring{A}$

for $L{i}^{2+}$ $r=a_0\frac{1^2}{3}$

$=\frac{0.530}{3}=0.176\mathring{A}$

Hence, option $C$ is correct.