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Atoms of individual elements emit light at only specific wavelengths, producing a line spectrum rather than the continuous spectrum of all wavelengths produced by a hot object. Niels Bohr explained the line spectrum of the hydrogen atom by assuming that the electron moved in circular orbits and that orbits with only certain radii were allowed.
A spectrum may be continuous, or may comprise bright lines (an emission spectrum), or dark lines (an absorption spectrum) superimposed on a background. A continuous spectrum results when the gas pressures are higher, so that lines are broadened by collisions between the atoms until they are smeared into a continuum.
The colors in the hydrogen emission spectrum correspond to wavelengths of 410.1, 434.1, 486.1, and 656.3 nm. The line spectra below are for lithium and sodium. We see that sodium has two yellow lines that are typical of some street lights. When heated, elements will produce line spectra.
This light in a line spectrum shows four visible wavelengths when passed through a prism, see in Figure 2. Compare the two types of emission spectra: continuous spectrum of white light (top) and the line spectra of the light from excited sodium, hydrogen, calcium, and mercury atoms.
A spectral line is a spectrum in which light of only a certain wavelength is emitted or absorbed, rather than a continuous range of wavelengths, rather than a continuous range of colours. Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium.
Bright line spectra as emitted by an excited gas The relationship between color, wavelength, frequency and energy. Read through the Introduction to review about light energy and the equations needed to calculate the energy of a photon and its frequency.
3 Σεπ 2009 · I. Introduction. This handbook is designed to provide a selection of the most important and frequently used atomic spectroscopic data in an easily accessible format. The compilation includes data for the neutral and singly-ionized atoms of all elements hydrogen through einsteinium (Z = 1-99).
