Q. The radius of hydrogen atom in the ground state is 0.53Å. The radius of $Li^{2 +}$ ion (atomic number =3) in a similar state is
A) 0.176 Å
B) 0.30 Å
C) 0.53 Å
D) 1.23 Å
Explanation
(a)
$r_{n} = \frac{r_{0} \times n^{2}}{Z}$
Given, $r_{0}$= radius of H atom in ground state =0.5Å
$n = number\ of\ orbit = 1$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ Z = \ atomic\ number\ of\ Li = 3$
$\therefore\ \ \ \ \ \ \ \ \ \ \ \ \ r_{n} = \frac{0.53 \times 1^{2}}{3} = 0.176\ \mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.