Can you fix a car engine?
It’s not as common any more, but there was a time when many people could work on their own cars if there was a problem. Today, engines are computerized and require specialized training and tools in order to be fixed. When people did their own repairs, it was sometimes a trial and error process. Maybe the parks plugs needed to be replaced. No, that didn’t fix the problem completely, but it was a start in the right direction. Science operates the same way. A theory that is developed may work for a while, but then there are data that the theory cannot explain. This means that it's time for a newer and more inclusive theory.
Spectral Lines of Hydrogen
Bohr’s model explains the spectral lines of the hydrogen atomic emission spectrum. While the electron of the atom remains in the ground state, its energy is unchanged. When the atom absorbs one or more quanta of energy, the electron moves from the ground state orbit to an excited state orbit that is further away. Energy levels are designated with the variable
The change in energy,
Based on the wavelengths of the spectral lines, Bohr was able to calculate the energies that the hydrogen electron would have in each of its allowed energy levels. He then mathematically showed which energy level transitions corresponded to the spectral lines in the atomic emission spectrum (Figure below).
He found that the four visible spectral lines corresponded to transitions from higher energy levels down to the second energy level
Bohr’s model was a tremendous success in explaining the spectrum of the hydrogen atom. Unfortunately, when the mathematics of the model was applied to atoms with more than one electron, it was not able to correctly predict the frequencies of the spectral lines. While Bohr’s model represented a great advancement in the atomic model and the concept of electron transitions between energy levels is valid, improvements were needed in order to fully understand all atoms and their chemical behavior.
- Emission lines for hydrogen correspond to energy changes related to electron transitions.
- The Bohr model works only for the hydrogen atom.
- What happens when a hydrogen atoms absorbs one or more quanta of energy?
- How do we detect the change in energy?
- What electron transitions are presented by the lines of the Paschen series?
- Does the Bohr model work for atoms other than hydrogen?