I am feeling a little stupid asking this considering I am about to graduate with my BS in chemistry. But I have never given this much thought, nor do I remember learning this and I cant figure out a proper explanation. Im sure I am overlooking a simple detail, but I can not figure it out. Ok, so I understand the bohr model and the principles behind photon absorption/emission perfectly fine. But one thing that is puzzling to me is why is it when the bohr model is applied to an atom such as hydrogen, only 4 emission lines observed? Can't it have more? I ask this because, the energy levels, n, go from n=0,1,2,3,4,...,infinity, right? So obviously there are more than 4 different energy levels that are capable of emitting a photon. Anybody have an answer? *edit* I think I figured it out...is it due to when n>4 that the only wavelength emitted are beyond the visible spectrum, thus meaning it is not visible to us?