How did Bohr's model improve atomic understanding?

Bohr's model improved atomic understanding by introducing quantised energy levels for electrons in atoms.

Niels Bohr, a Danish physicist, proposed his model of the atom in 1913, which was a significant improvement on the earlier models proposed by J.J. Thomson and Ernest Rutherford. Bohr's model was revolutionary because it introduced the concept of quantised energy levels for electrons in atoms. This meant that electrons could only exist in specific energy states, and they could move between these states by absorbing or emitting energy.

Before Bohr's model, the atomic model proposed by Rutherford had a major flaw. It suggested that electrons orbit the nucleus in a similar way to planets orbiting the sun. However, according to classical physics, electrons moving in such orbits would continuously lose energy and eventually spiral into the nucleus, leading to the collapse of the atom. This clearly contradicted the stability of atoms observed in reality.

Bohr resolved this issue by proposing that electrons in an atom could only occupy certain fixed orbits, or energy levels. An electron could move from a lower energy level to a higher one by absorbing a specific amount of energy, or drop from a higher energy level to a lower one by emitting a specific amount of energy. This energy was often in the form of light, which explained the line spectra observed in experiments.

Bohr's model was also able to accurately predict the spectral lines of the hydrogen atom. This was a significant achievement, as no previous model had been able to do this. The model suggested that the different spectral lines corresponded to different transitions between energy levels of the electron in the hydrogen atom.

However, Bohr's model was not without its limitations. It worked well for single-electron systems like hydrogen, but could not accurately predict the behaviour of multi-electron atoms. Despite this, Bohr's model was a crucial step forward in the development of quantum mechanics, and it greatly improved our understanding of atomic structure.