Bohr’s perfectly-defined orbits were replaced with probability “clouds” where by an electron is probably going to be. The Niels Bohr Institute, Portion of the College of Copenhagen The Bohr model worked perfectly for hydrogen and ionized one-electron helium which amazed Einstein[56][57] but could not demonstrate a lot more elaborate things. https://un-kind.de/innovationen-in-der-bohrmaschinentechnologie-was-sie-wissen-mussen/