Question

How does the Bohr theory account for the observed phenomenon of the emission of discrete wavelengths of light by excited atoms?

Short answer

The Bohr theory accounts for the observed phenomenon of discrete wavelengths of light emitted by excited atoms by proposing that electrons revolve around the nucleus in specific stable orbits with quantized energy levels. When an electron transitions between these energy levels, it emits or absorbs a photon with an energy equal to the difference between the initial and final energy levels, corresponding to a specific wavelength of light. As a result, the observed emission spectrum of an atom consists of discrete wavelengths or lines, which are unique for each element, producing a characteristic spectrum.

Step-by-step solution

1. Understand the fundamentals of the Bohr Theory

The Bohr theory is based on two main assumptions: 1. Electrons revolve around the nucleus in certain specific stable orbits without radiating energy. These orbits are called "allowed orbits" or "stationary states". Each orbit is associated with a specific amount of energy. 2. The electron can change its orbit by gaining or losing specific amounts of energy. To do so, electrons have to absorb or release energy as a photon, with its energy (E) related to the frequency (f) of the emitted or absorbed radiation by the formula, E = h*f, where h is Planck's constant.

2. Energy levels and the emission of radiation

The Bohr theory states that an electron can move from one energy level to another without emitting any radiation. However, when an electron goes from a higher energy level to a lower one, radiation is emitted in the form of a photon. The energy of this photon corresponds to the change in energy between the two energy levels.

3. Discrete wavelengths of emitted light

In the Bohr theory, the energy levels of the electrons in an atom are quantized, meaning they can only take certain specific values. When an electron transitions between two energy levels, it emits or absorbs a photon with an energy equal to the difference between the initial and final energy levels. This energy difference corresponds to a specific wavelength of light, and as a result, the observed emission spectrum of an atom consists of discrete wavelengths, or lines, corresponding to the various possible transitions between energy levels. Because the allowed energy levels are unique for each element, the wavelengths of emitted light will also be unique, producing a characteristic spectrum for each element.

4. Applications of Bohr's theory to explain observed phenomena

The discrete wavelengths of emitted light from excited atoms can be explained using the Bohr theory, which predicts the specific energy levels allowed for electrons in an atom. These discrete wavelengths correspond to the radiation emitted when electrons move from one energy level to another. To account for the observed phenomenon of discrete wavelengths of light emitted by excited atoms, Bohr's theory offers a helpful framework to understand the quantized energy levels of electrons and their transitions between these levels. This theory not only helps to explain the characteristic spectra for individual elements but also has significant applications in understanding atomic structure and chemical properties.