The discreteness of energy levels is best understood by considering the electrons to be wave like.
This above can be explained on the basis of bohr model and wave mechanical theory.
According to bohr's atomic model, the angular momentum of electron orbiting around the nucleus is an integral multiple of h/2π.
The electron in the atom moving around the nucleus of an atom. The wave mechanical theory proposes that each electron revolving an atom's nucleus occupies a specific orbital and spins in a certain direction, but the orbitals is like a wave of energy.
The wave mechanical model proposed that the electron acts like particles as well as wave of energy. According to the field around, the electron changes there path and they start moving very fast act like wave of energy and hence they are not in place during any particular time.
Thus we concluded that electron revolve around central nucleus at such high speed that they act like wave of energy.
learn more about wave mechanical theory:
https://brainly.com/question/21154039
#SPJ4