Visible spectrum of hydrogen

In 1885, Johann Balmet a mathematician, derived the following relation for the wavelength of lines in the visible spectrum of hydrogen... 

Fig. 17-3 The origin of the visible spectrum of hydrogen (not drawn to scale)...

Figure 3.1 The visible spectrum of hydrogen, called the Bahner series. The wavelengths of these spectral lines are, from left to right, 4,101.2 A, 4,340.1 A, 4,860.74 A, and 6,562.10 A.

Calculate the frequency of a photon of light of wavelength 6.563 X 10 m, corresponding to a line in the visible spectrum of hydrogen. 

Scientists in the late nineteenth century tried to quantify the hne spectra of the elements. In 1885 the Swedish school teacher Johann Raimer discovered a series of lines in the visible spectrum of hydrogen, the wavelengths of which could be related with a simple equation ... 

The line spectrum of the hydrogen atom is especially simple. In the visible region, it consists of only four lines (a red, a blue-green, a blue, and a violet), although others appear in the infrared and ultraviolet regions. In 1885 J. J. Bahner showed that the wavelengths A in the visible spectrum of hydrogen could be reproduced by a simple formula ... 

In 1932, Urey noticed that a considerably over-exposed photograph of the visible spectrum of hydrogen showed weak satellite lines on the short wavelength side of the normal Balmer series. He made the (now) obvious conclusion that these satellite lines were due to an isotope of hydrogen, namely deuterium. If the H< line and its satellite were observed at 6564.6 and 6562.8 A, respectively, calculate the ratios M lm and Af2/Mi, where m, M, and Ml are the masses of the electron, the proton, and the deuterium nucleus, respectively. Given ... 

Draw a picture of the electron jump corresponding to the first line in the visible emission spectrum of hydrogen according to the Bohr theory. 

Figure 12.6 The emission spectrum of hydrogen in the UY, visible and near infrared, showing the families of lines labeled Lyman (n = 1), Balmer (n — 2), and Paschen (n = 3).

There are definite distinct lines in the atomic emission spectrum of hydrogen. These lines are seen in the visible part of the spectrum and there is also a series of lines in the infrared and another series in the ultraviolet part of the electromagnetic spectrum. So, although hydrogen is the simplest element with only one electron per atom, its atomic emission spectrum is fairly complicated. 

The atomic emission spectrum of hydrogen is composed of many lines but these fall into separate sets or series. The first series to be discovered, not surprisingly, were those lines in the visible part of the spectrum. In 1885, a Swiss schoolmaster, Johann Balmer, noticed that the wavelengths, A, of the lines in this series could be predicted using a mathematical formula. He did not see why he just saw the relationship. This was the first vital step. 

As a result of his work, the lines in the visible spectrum are known as the Balmer series. The other series of lines in the atomic emission spectrum of hydrogen were discovered later (the next wasn t discovered until 1908). These series are named after the scientists who discovered them for example, the series in the ultraviolet region is known as the Lyman series after Theodore Lyman. 

Uranium hexachloride is a black solid melting at 177.5°. Since it is hygroscopic and reacts vigorously with water, it should be handled only in dry-boxes. The crystal structure has been determined hexagonal symmetry, space group D a-C7> (m, n = 3), with an almost perfect octahedron of chlorine atoms around each uranium atom. Uranium hexachloride can be sublimed at 75-100° at low pressures, but normally some thermal decomposition results. The ultraviolet-visible spectrum of gaseous uranium hexachloride has been determined. No fine structure was observed in the spectrum. Because previously available preparative methods were inadequate, there has been very little study of the chemistry of uranium hexachloride. It reacts with hydrogen... 

Find the energy of the transition from /, = 3 to w = 2 for the hydrogen atom in both joules and cm (a common unit in spectroscopy). This transition results in a red line in the visible emission spectrum of hydrogen. (Solutions to the exercises are given in Appendix A.)... 

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