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XIV. Theoretical Aspects of the Neon Spectrum. 

 By Laurence St. C. Broughall *. 



T^HE object of this paper is to attempt to explain the 

 spectrum o£ neon in a manner somewhat similar to 

 that used by Bohr f in his explanation o£ the reason for the 

 existence of the Balmer series in the hydrogen spectrum. 



The principle on which this hypothesis rests is that when 

 an electron rotates in a fixed orbit it does not radiate energy, 

 although the principles of electrodynamics state that it 

 should ; if, however, the electron changes from one orbit 

 to another, then energy is emitted, provided that the kinetic 

 energy of the electron is less in the second orbit than in the 

 first. 



In order to account for the spectrum, it is assumed that 

 the energy emitted is numerically equal to the product 

 of the frequency of the spectral line produced and the 

 quantum constant. We thus obtain the equation 



E = nA, 



where E = energy emitted, n = frequency of the resulting 

 radiation, and h = quantum constant. 



In the case of hydrogen, it was assumed that the orbit of 

 the electron was circular, and then the attractive force 

 between nucleus and the electron due to their equal and 

 opposite charges was balanced by the centrifugal force of 

 the electron due to its rotation about an axis passing through 

 the nucleus. 



The energy of the electron can thus be found for any 

 radius of orbit. When the electron changes its orbit, it 

 moves to one with a radius which is an exact multiple of the 

 radius of the original orbit. In this manner the change of 

 energy due to a change of orbit can be found, and then, 

 using the equation given above, it was shown by Bohr how 

 the constant of the Balmer series could be found ; and the 

 value so obtained agreed extremely well with that found by 

 experiment. 



In the case of neon, we are dealing with an atom which 

 contains more than one electron ; and since the atomic 

 number is 10, it follows that if the atom is to be neutral, 

 then there must be 10 electrons present to annul the excess 

 of 10 positive charges in the nucleus. 



* Communicated by the Author. 

 t Phil. Mag. vol. xxix. p. 332. 



