Discussion Forum

From the following energy levels of hydrogen atom, the value of $E_{\infty}$ and $E_{3}$ in J are, respectively

______________   $E_{\infty}$`=-------------

______________ $E_{3}$ =----------------

______________ $E_{2}=-0.545 \times  10^{-18} J$

_____________  $E_{1}=-2.18 \times 10^{-18} J$

Answer:

Explanation:

$ E_{n}=-2.18 \times 10^{-18}. \frac {Z^{2}}{n^{2}}$

where, E_n  = energy of an electron  in nth orbital.

        Z= atomic number

      n= number of orbital

 For hydrogen , Z=1

 Therefore,

$E_{3}=-2.18\times 10^{-18}\times\frac{1}{3^{2}}$

 $=-\frac{2.18\times 10^{-18}}{9}$

 =$-0.242 \times 10^{-18}$

 and    $E_{\infty}=-2.18 \times 10^{-18}\times \frac{1}{\infty}$

   $E_{\infty}=0$

 Hence, $E_{\infty}$=0   and $E_{3}=-0.242 \times 10^{-18}$

 and option (c) is the correct answer.