If I am not mistaken the Bohr model had 3 main problems: the assumption that the electron moves in fixed orbits, the angular momentum assumption's violation of the Heisenberg uncertainty principle, and finally the restriction of the validity of the model for only 1-electron systems ( i.e. hydrogen, He +1, ect ). Why was it that Bohr's model only worked for 1-electron systems and failed when applied to poly-electron systems? Please be as thorough as possible. Thank you for all your help.