Question

The energy of an electron in the $3\,S$ orbital (excited state) of $H$ - atom is

• A. - 1.5 eV
• B. - 13.6 eV
• C. - 3.4 eV
• D. - 4.53 eV

Answer 1

Answer: (A)

- 1.5 eV

Answer 2

(i) Energy $(E)$ of $n=1$ i.e. is,

$=-\frac{13.6 .z^{2}}{n^{2}} eV$
$=-\frac{13.6 \times 1}{1}=-13.6\, eV$

(ii) For $n=3$ i.e. $3 s$
$E=-\frac{13.6}{(3)^{2}}$
$=-\frac{13.6}{9} eV$
$=-1.5 \,eV$