Question

The electron energy in hydrogen atom is given by $E_n=(-2.18\times {10}^{-18})n^2$ joules.Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength (in A ) of light that can be used to cause this transition.

Answer 1

$E_n=(-2.18\times {10}^{-18})n^{2}joule$

Energy required to remove an electron completely from $n=2$ orbit

$E_2=(-2.18\times {10}^{-18})2^2$

$=-8.72\times {10}^{-18}$

$8.72\times {10}^{-18}=\frac{hc}{\lambda }$

$\lambda =\frac{6.626\times {10}^{-34}\times 3\times {10}^8}{8.72\times {10}^{-18}}$

$=2.27958\times {10}^{-8}m$

$=227.96A^o$