What is the explanation for the discrete lines in atomic emission spectra?
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The discrete lines observed in atomic emission spectra can be explained by considering the energy levels of electrons in atoms.
When an atom is excited, for example, by passing an electric current or heating it, the electrons in the atom absorb energy and move to higher energy levels. These higher energy levels are unstable, and the electrons eventually return to their original energy levels by releasing the excess energy they gained.
The release of this excess energy is what causes the emission of light. Each electron transition corresponds to a specific energy difference between energy levels, which in turn corresponds to a specific wavelength or color of light.
The energy levels in atoms are quantized, meaning that only specific energy values are allowed. This leads to the emission of light of specific wavelengths or colors, resulting in the discrete lines observed in atomic emission spectra.
To determine the specific wavelengths or colors of light emitted by an atom, scientists can use a technique called spectroscopy. By passing the emitted light through a prism or a diffraction grating, the light is separated into its constituent colors, forming a spectrum. The positions of the discrete lines in the spectrum can then be measured and compared to known values to identify the elements present in the sample.