Question

Calculate the energy, frequency, and wavelength required to remove the electron from the H atom, if the electron is in the n=2 energy level. Is the transition visible?

Answer 1

for Hydrogen,

En = -13.6/n^2 ev

So, energy for n=2 is,

E = -13.6/2^2 = -3.4 eV

1)

Energy required = 3.4 eV

E = 3.4 eV

= 3.4*1.602*10^-19 J

= 5.45*10^-19 J

Answer: 5.45*10^-19 J

2)

use:

E = h*f

5.45*10^-19J =(6.626*10^-34 J.s)*f

f = 8.225*10^14 Hz

Answer: 8.225*10^14 Hz

3)

use:

E = h*c/lambda

5.45*10^-19J =(6.626*10^-34 J.s)*(3.0*10^8 m/s)/lambda

lambda = 3.647*10^-7 m

Answer: wavelength = 3.647*10^-7 m

4)

wavelength = 3.647*10^-7 m

wavelength = 365 nm

wavelength of visible light is 400 nm to 700 nm

This is not in this range

Answer: no