Question

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

• A. $1$
• B. $\frac{1}{2}$
• C. $\frac{3}{2}$
• D. $2$

Answer 1

Answer: (A)

Value of $Z$ for hydrogen = $1$
Value of $Z$ for helium = $2$
Value of $n$ for both is = $1$
$r_H=\frac{0.52\times 1^2}{1}{r}_{H{e}^{+}}=\frac{0.52\times 1^2}{1}$
$\frac{r_H}{r_{H{e}^{+}}}=1:1$ or $r_{H{e}^{+}}:r_H=1:1$