Niels Bohr was awarded the Nobel Prize in physics in 1922 for his work investigating the structure of an atom.Does not match what scientists would later learn that an electron can be both a wave and a particle.

The Bohr model did not describe the changes seen in emission spectra when a magnetic field was present (known as the Zeeman effect).The atomic model could not explain the different line intensities in emission spectra.The emission spectrum of atoms with more than one electron could not be explained. The Bohr atomic model could not accurately describe larger atoms.Hydrogen and other 1 electron systems are the only ones accurately explained by the Bohr Model Problems with Bohr’s Model When there is more than one electron interactions between the nucleus and electrons become too complicated for the Bohr model.ĭepiction of the Bohr model of hydrogen. Other ions that also have one electron can also be explained accurately (for example, He +). When there is more than one electron the model does not accurately predict the energies. The Bohr model of hydrogen is the only one that accurately predicts all the electron energies. Previous models had not been able to explain the spectra. Using Bohr’s model of the atom the previously observed atomic line spectrum for hydrogen could be explained. No other model had done this before and was a big step towards the development of quantum mechanics. It is the first atom model that accounts for quantized or discrete energy steps.

Thomson in 1904), the Saturnian model (by Hantaro Nagaoka in 1904), and the Rutherford model (by Ernest Rutherford in 1911).īohr’s model is different from the preceding model (the Rutherford model) because electrons can only orbit at certain radii or energy. The Bohr model replaced earlier models such as the plum-pudding model (by J.J. (From Wikipedia Commons) Improvements From Previous Models Each orbit change has a unique energy difference.Ītomic line spectra of hydrogen. And the blue line would be caused by an electron moving from shell 3 to shell 2. For example, the red line would be caused by the electron moving from shell 2 to shell 1. Only light of specific energy (or color) is released, shown by the sharp lines seen in the spectra, not all colors of light. These discrete energy steps are what cause atomic line spectra, like the one seen for hydrogen below. The energy is released in the form of light. When the electron moves from a larger higher-energy shell to a smaller lower-energy one it releases energy. When an electron moves to a smaller shell, it releases energy which we observe as light.

Atom drawing