Question

When hydrogen atom is in its first excited level, it's radius is

• A. Four times greater than its ground state radius
• B. Two times greater than itsground state radius
• C. Same as ground state radius
• D. Half of ground state radius

Answer 1

Answer: (A)

Four times greater than its ground state radius

$r_n=r_o.n^2$, where $r_o$ is radius of ground-state & $r_n$ is radius of $n^{th}$ state. (For first excited state $n=2)$.

$r_n=4r_0$