Influence of Orbitals on the mass of the electron

[Uzbar Zibil Tarag]

If Energy levels differ in accordance to the orbital, say like 2s and 3d orbitals, then shouldn't the mass of the electron then change to uphold E=mc^2?
Or is there something I am missing?

 

[Drakkith]

You are correct in that the mass changes, but it isn't the mass of the electron that changes, it's the mass of the atom as a whole. In other words, an atom of hydrogen has slightly less mass than the sum of the masses of a free proton and free electron. This mass difference is proportional to the energy emitted when the electron and proton combine, with the exact amount found by using e=mc².

 

[Uzbar Zibil Tarag]

While that does make sense, if the mass of the atom as a whole changes and the electrons don't change mass, then do the Neutrons or Proton, or in the case of the Hydrogen example, just the proton change mass to account for this change?

 

[Drakkith]

As far as I understand it, you can't say anything about the masses of each subatomic particle while they're bound in an atom. You can only say that the atom as a whole has less mass than the sum of the masses of the free particles. Perhaps someone more knowledgeable on this topic can explain it better than I can.