The Atomic Spectrum of Hydrogen

What is the significance of the line spectrum of hydrogen It indicates that only certain energies are allowed for the electron in the hydrogen atom. In other words, the energy of the electron in the hydrogen atom is quantized. 

Experiment 21 Spectroscopy 1 Spectra of Atomic Hydrogen and Nitrogen 

Spectrum adapted by permission from C. W. Keenan, D. C. Kleinfelter, andj. H. Wood, General College Chemistry, Sixth Edition (New York Harper Row, 1980). 

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The discrete line spectrum of hydrogen shows that only certain energies are possible that is, the electron energy levels are quantized. In contrast, if any energy level were allowed, the emission spectrum would be continuous. 

We now have evidence that electron energy levels in the atoms are quantized. Some of this evidence is discussed in this chapter. What if energy levels in atoms were not quantized What are some differences we would notice  

To understand the significance of the hydrogen emission spectrum, we must first describe the continuous spectrum that resuits when white iight is passed through a prism, as shown in Fig. 7.7(a). This spectrum, iike the rainbow produced when sunlight is 

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A change between two discrete energy levels emits a photon of light. 

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The hydrogen atom, containing a single electron, has played a major role in the development of models of electronic structure. In 1913 Niels Bohr (1885-1962), a Danish physicist, offered a theoretical explanation of the atomic spectrum of hydrogen. His model was based largely on classical mechanics. In 1922 this model earned him the Nobel Prize in physics. By that time, Bohr had become director of the Institute of Theoretical Physics at Copenhagen. There he helped develop the new discipline of quantum mechanics, used by other scientists to construct a more sophisticated model for the hydrogen atom. 

The Brackett series lines in the atomic spectrum of hydrogen result from transitions from n > 4 to n = 4. 

Figure 1.4. A part of the atomic spectrum of hydrogen (/. = wavelength)...

The quantum theory, however, is essentially a physical theory, developed to explain observations like the atomic spectrum of hydrogen. Chemical ideas do not emerge from it easily. The theory is also very mathematical. Most chemists have to accept the results of quantum-mechanical calculations on trust. My approach avoids these problems. While I bring in the quantum theory where it is helpful, my treatment is essentially chemical. This makes for an easier introduction to the subject, and leads, I believe, to a better understanding of the key ideas, and the chemical thinking behind them. 

IBLG See questions from The Nature of Matter and the Atomic Spectrum of Hydrogen ... 

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