From what I've learned in physics, electrons falling from higher energy levels to a lower energy level emits an photon equal to that of the difference in energy between the two levels. Each atom has a set number of energy levels for the electrons, and thus each element can only emit a set number of photon wavelengths. Given there are limited numbers of elements, and a limited number of energy levels for each electron, does that mean the number of wavelengths for photons is limited also? Meaning, there isn't a continuous spectrum for EM radiation, rather quantized wavelengths, while some wavelengths don't exist? (i.e. say if no electron in any element have levels have the energy correlated to a photon of 345 nm, then such a photon doesn't exist in nature). Or am I misinterpreting something?