Rutherford, Bohr and Balmer

Should it surprise us that the model these fellows concocted worked so remarkably well to explain so many chemical phenomena In fact, it worked to such an extent that it is still being taught to high school students today, a hundred years later. It had only a few parameters to adjust, namely number and capacity of orbits of electrons and rules for losing, gaining and sharing of outside electrons. Yet it explained, in the end, a virtual infinity of chemical reactions of wide ranging variety. No wonder that the picture Bohr 

Only certain frequencies were emitted. For a given type of atom, always the same frequencies were present. Atoms of different substances had a characteristic spectrum , as it was called. Bohr explained this phenomenon in terms of his own model of the atom by saying that the orbits containing electrons occurred at discrete intervals, pictured as distances from the nucleus, and that electrons had to jump from one of these to the next in a more or less discontinuous fashion, so that the difference in energy required to promote the electron resulted in a discrete line appearing in the spectrum of the atom. 

quantum mechanics would offer a mathematical model of the energy states of the hydrogen atom and it would yield shapes like the one shown in Fig. 1.3, which, of course, blow to bits our beloved image of the hydrogen atom as a little star with a fast little planet circling it. 

---