How did Bohr explain the phenomenon of atomic emission spectra?

Bohr's model of the atom provided a significant advancement in understanding atomic structure and behavior, particularly regarding the emission spectra. He proposed that electrons exist in specific energy levels or orbits around the nucleus and that these energy levels are quantized, which means that electrons can only occupy certain allowed energies.

In this context, when electrons absorb energy—such as from heat or light—they can become excited and jump to a higher energy level. However, this state is unstable, and the electrons eventually return to their original, lower energy levels. As they do so, they release the energy they absorbed in the form of light. This emitted light corresponds to specific wavelengths, which is observed as the atomic emission spectrum.

Thus, Bohr explained that the emission of light by atoms occurs specifically when electrons transition between different energy levels. This concept of quantized energy levels not only elucidates the mechanism behind atomic emission spectra but also aligns with experimental observations, making it a cornerstone of quantum chemistry.