These observed spectral lines are due to the electron making transitions between two energy levels in an atom. The emission spectrum of atomic hydrogen has been divided into a number of spectral series, with wavelengths given by the Rydberg formula. Emission spectra If an electron is in an excited state it can return to a lower energy level. This means that line spectra can be used to identify elements.Ĭontinuous spectra are produced by electrons being shared between many atoms, giving a huge range of possible frequencies, as shown below. The spectral series of hydrogen, on a logarithmic scale. As a result each produces photons with different energy and so the line spectra for different elements will be different. This is not a continuous spectrum as only light of specific frequencies and specific colours are produced.ĭifferent types of atoms have different energy levels. The hydrogen emission spectrum comprises. from the Calculation Investigation) that the the frequency is given by n c / l, and the energy is given by E hn (where h 6.626 x 10 -34 J-s, and c 3 x 10 8 m/s). Measuring from the scale, the wavelengths are 435 nm (purple), 486 nm (blue) and 657 nm (red). This causes line emission spectra to be produced, as shown below. Line spectra is the emission of electromagnetic radiation initiated by the energetically excited hydrogen atoms. We can identify three bright lines for hydrogen in the top spectrum. This means that each electron transition will produce a photon of a different frequency and hence a different colour. \(f\) is the frequency of light producedĪs the energy levels have different values, each of the possible electron transitions within an atom will produce a photon with a different energy.If an electron moves from level \(E_\) the energy of the photon can be worked out using the following: The energy of the photon can be worked out using the equation The amount of energy it loses will be equal to the difference in the energy levels it moves between. 1.3: Photoelectric Effect Explained with Quantum Hypothesis 1.5: The Rydberg Formula and the Hydrogen Atomic Spectrum Overview To introduce the concept of absorption and emission line spectra and describe the Balmer equation to describe the visible lines of atomic hydrogen. If an electron is in an excited state it can return to a lower energy level.
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