So we're getting somewhere! We are able to explain experimental spectral lines with the Bohr model. Fantastic!
There's only one problem though. When he attempted to explain any other element in nature with his equations, he was no longer able to accurately predict the wavelengths observed in the elements' emission spectra. There must be something missing from Bohr's model that will allow us to explain the location of the electron.
The main problem with Bohr's model is that he fails to acknowledge that electrons occupying the same electron shell will experience repulsions. His model accounts for the attraction between the positive nucleus and the one negative electron found in hydrogen. Since all electrons are negatively charged, if additional electrons are forced to occupy the same electron shell, they will repel each other. Even the next simplest element found in nature, helium, will have 2 electrons in the first electron shell, so Bohr's model cannot be used to accurately predict the behavior of helium's electrons.
There are other significant problems with the Bohr atom that are beyond the scope of the course which deal with quantum mechanics. Just realize that Bohr's model is unable to predict the bright-line spectra of multi-electron atoms.
