Question

The ratio between radii of $H{e}^{+}$ ion and H atom is

• A. 1/2
• B. 1
• C. 3/2
• D. 2

Answer 1

The correct option is

B

Value of Z for hydrogen = 1
Value of Z for helium = 2
Value of n for both is = 1

radius of orbit =$0.53\times \frac{n^2}{Z}{A}^0$

$r_H=\frac{0.5\times 1^2}{1}{r}_{H{e}^{+}}=\frac{0.52\times 1^2}{2}$
$\frac{r_H}{r_{H{e}^{+}}}=1:2or{r}_{H{e}^{+}}:r_H=2:1$