Question

The ratio of difference between $3^{rd}$ and $2^{nd}$ orbit of H atom and $L{i}^{2+}$ ion is

• A. $5:15$
• B. $15:5$
• C. $5:3$
• D. $3:5$

Answer 1

The correct option is B $15:5$

$\text{Radius of H like species}=0.529\frac{n^2}{Z}\stackrel{\circ }{A}$

For H,

$r_3-r_2=0.529(\frac{9}{1}-\frac{4}{1})=0.529\times 5\stackrel{\circ }{A}$

For $L{i}^{2+}$,
$r_3-r_2=0.529(\frac{9}{3}-\frac{4}{3}=0.529\times \frac{5}{3}\stackrel{\circ }{A}$

$\text{The ratio of differences}=5:\frac{5}{3}=15:5$