Scientists made the following two observations about emission spectra:
Each element has a unique emission spectrum.
Atoms emit energy only at specific wavelengths.
Describe how the Bohr model explains both of these observations.
The Bohr model, proposed by Niels Bohr in 1913, explains both observations about emission spectra.
The first observation states that each element has a unique emission spectrum. This means that when an element is excited (e.g., by heat or electricity), it emits light at specific wavelengths that are characteristic of that element. The Bohr model explains this by proposing that electrons in an atom can only occupy certain discrete energy levels or orbits. When an electron in a higher energy level jumps to a lower energy level, it emits energy in the form of light at a specific wavelength corresponding to the energy difference between the two levels. Since each element has a unique electron configuration or set of energy levels, the emitted light will have a distinct set of wavelengths or emission spectrum associated with that element.
The second observation states that atoms emit energy only at specific wavelengths. This means that in an emission spectrum, there are no continuous bands of light, but rather, distinct lines are observed. The Bohr model explains this by suggesting that electrons can only have specific energy values or levels, and can only transition between these levels in discrete steps. These specific energy levels correspond to the orbits or shells in the Bohr model. When an electron jumps from a higher energy level to a lower energy level, it emits a photon of light with an energy equal to the energy difference between the two levels. Since the energy of light is directly proportional to its frequency, this leads to the emission of light at specific wavelengths, resulting in the observed discrete lines in the emission spectrum.
Therefore, the Bohr model explains both observations about emission spectra by proposing that electrons can only exist in specific energy levels within an atom, and their transitions between these levels result in the emission of light at specific wavelengths, yielding a unique emission spectrum for each element.