Review of Bohr's model of hydrogen

As we have seen in a previous article, the emission spectra of different elements contain discrete lines. The following image shows the visible region of the emission spectra for hydrogen.

 

The quantized emission spectra indicated to Bohr that perhaps electrons could only exist within the atom at certain atomic radii and energies. Recall that quantized refers to the fact that energy can only be absorbed and emitted in a range of allowable values rather than with any possible value. The following diagram of the Bohr model shows the electron existing in a finite number of allowed orbits or shells around the nucleus.

 

From this model, Bohr derived an equation that correctly predicted the various energy levels in the hydrogen atom, which corresponded directly to the emission lines in the hydrogen spectrum. Bohr's model was also successful at predicting the energy levels in other one-electron systems, such as $\text{He}^+$He​+​​H, e, start superscript, plus, end superscript. However, it failed to explain the electronic structure in atoms that contained more than one electron.

While some physicists initially tried to adapt Bohr's model to make it useful for more complicated systems, they eventually concluded that a completely different model was needed