Why is the colour of the light emitted by an element in its gaseous state characteristic of the element? And why does hydrogen with only one electron have so many spectral lines? I have some idea but I need to clarify my understanding against someone else's view. I would be very grateful for some help.

Question

Every element and molecule has only a certin set of allowed energy states. The exact energy of those stetes depends upon the number of electrons and (for molecules) the arrangement of nuclei. Spectral lines that you observe have frequencies proportional to the energy difference between the states involves in the transition

Thanks very much for your help