Q. Which state of triply ionized Beryllium $(Be^{+ + +})$ has the same orbital radius as that of the ground state of hydrogen
A) $n = 4$
B) $n = 3$
C) $n = 2$
D) $n = 1$
Explanation
(c) Radius of $n^{th}$ orbit for any hydrogen like atom
$r_{n} = r_{0}\left( \frac{n^{2}}{Z} \right)$ ($r_{0} =$ radius of first orbit of $H_{2}$-atom)
If $r_{n} = r_{0} \Rightarrow n = \sqrt{2}$. For $Be^{+ + +},Z = 4 \Rightarrow n = 2$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.