[johndb]

Can anyone recommend a good website or resource on/ or perhaps briefly explain the following areas/questions; how were atomic energy levels determined because I've often seen Rutherford's, J.J Thomson, Robert Millikan's experiments on discovering fundamental aspects of the atom, but I'm curious on the methods and procedures and history of discoveries involved in determining some of the other aspects of the atom that aren't elaborated on in most textbooks, like valence energy levels, ionization levels, how do/ did they determine the number of electrons on each element. Many such things that we are told but not how they know these things

[Borek]

how were atomic energy levels determined