Our goal with be to produce the energy level diagram from the electronic spectra. When the hydrogen atoms are hit by high energy electrons,the atoms absorb some of the electrons' energy.This produces atoms with higher energies. The atoms do not like to exist with these high energies so they radiate photons and go to a lower energy. The spectrum produced is not continous.; see below ; we are observeing  wavelenghts

           f                                     e        d                                         c            b     a

           |                                      |         |           x10(-7)  M               |             |       |                          18.803                          6.565     4.163                             1,216      1.026  .973

The following equations express what is going on.

E atom before rad.  -  E atom after rad  =  E photon = hf    Rerember according to Einstein. The energy of a photon is h (Planck's constant) times the frequency. Also the frequency times the wavelenght equals the speed of light. The speed of light is 3x10 (8) m/sec and Plank's const is 4.136x10(-15) ev sec. Using  these relationships, fill in the first 3 coluums of  the table shown below. You can not imput to the screen,so make a copy on a sheet of paper
   line  wavelenght frequency energy photon level  transistion
     a .973x10(-7)m 3.08x10 (-15) 12.75  ev 4  to  1
     b
     c
      d
      e
       f 
You are now ready to produce the energy level diagram for the hydrogen atom from the table just completed. Rerember the energy of a photon represents the difference between energy levels. How many levels do we needed to account for 6 lines?  We need four levels. see fig b.  Since line a has the smalllest wavelenght and the largest frequency, it represents photons of the greatest energy. It must be associated with the largest  energy change. Therefore,it 's transistion from level 4 to level 1.

                         17.75   ev         ____________________n=4
                                                  ____________________n=3

 

                                                  ____________________n=2

 

                              5ev               _____________________n=1

                                                         fig b

Since,the ground state is taken as 5ev and the difference between the levels is 12.75,therefore the value for the fourth level is 17.25. Fill in the transiston coluum in the first table,hint: as the value of the energiy levels  increases , the difference between levels decreases. Now, determine the values of the second and third levels. I have not been to explicit.;rerember we learn by doing;in other words I have tried to make this as close to a discovery lab without making it to frustrating.  You are on your own;don't expect to find the answers anywhere. ENJOY YOURSELF!

 

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