Emission spectrum, of hydrogen

CHAPTER 6 Quantum Theory and the Electronic Structure of Atoms 

Student Annotation Remember to keep at least one extra digit in intermediate answers to avoid rounding error in the final result [Mt Section 1.5]. 

Calculate the wavelength (in nm) of the photon emitted when an electron transitions from the n = 4 state to the n = 2 state in a hydrogen atom. 

Practice Problem A What is the wavelength (in nm) of a photon emitted during a transition from the n = 3 state to the = 1 state in the H atom  

Practice Problem B What is the value of i for an electron that emits a photon of wavelength 93.14 nm when it returns to the ground state in the H atom  

---

The Bohr atom went a long way toward explaining the nature of atoms, but there were problems. Although scientists could calculate the emission spectrum of hydrogen using the Bohr model, the model could not account for the spectra of heavier atoms. The biggest problem with the Bohr atom, however, lay in its lack of a... 

The discovery of two other series of emission lines of hydrogen came later. They are named for their discoverers the Lyman series in the ultraviolet range and Paschen series in the infrared region. Although formulas were devised to calculate the spectral lines, the physics behind the math was not understood until Niels Bohr proposed his quantized atom. Suddenly, the emission spectrum of hydrogen made sense. Each line represented the energy released when an excited electron went from a higher quantum state to a lower one. 

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

The first application of quantum theory to a problem in chemistry was to account for the emission spectrum of hydrogen and at the same time explain the stability of the nuclear atom, which seemed to require accelerated electrons in orbital motion. This planetary model is rendered unstable by continuous radiation of energy. The Bohr postulate that electronic angular momentum should be quantized in order to stabilize unique orbits solved both problems in principle. The Bohr condition requires that... 

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. 

You can get more information on the atomic emission spectrum of hydrogen by watching the video clips at www. brightredbooks.net... 

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. 

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.)... 

The electronic spectra of monoelectronic atoms can be interpreted on the basis of transitions of the electron between orbitals involving photons. However, not all photon-induced transitions are allowed to occur in this way. Figure 3.16 shows the main transitions responsible for the emission spectrum of hydrogen. 

The atomic emission spectrum of hydrogen consists of four distinct coiored iines of different frequencies. This type of spectrum is aiso known as a iine spectrum. Which iine has the highest energy ... 

Balmer series That portion of the emission spectrum of hydrogen in the visible portion representing electron transitions from energy levels n > 2 to n = 2. 

A green line of wavelength 4.86 X 10 m is observed in the emission spectrum of hydrogen. Calculate the energy of one photon of this green light. 

How did scientists account for the fact that the emission spectrum of hydrogen is not continuous but consists of only a few lines of certain colors ... 

MiniLab 2 Which of the lines of the visible emission spectrum of hydrogen represents the greatest energy drop ... 

Just as the emission spectrum of hydrogen has four characteristic lines that identify it, so the emission spectrum for each element has a characteristic set of spectral lines. This means that the energy levels within the atom must also be characteristic of each element. But when scientists investigated multi-electron atoms, they found that their spectra were far more complex than would be anticipated by the simple set of energy levels predicted for hydrogen. Figure 7.4 shows spectra for three elements. 

Let us investigate the situation in molecular spectroscopy. As the basic example we take the paper on the emission spectrum of hydrogen fluoride by Mann, Thrush, Lide, Ball, and Acquista,1 in which a given vibra-tion/rotation band is analyzed with the relation... 

The emission spectrum of hydrogen includes a wide range of wavelengths from the infrared to the ultraviolet. Table 7.1 lists the series of transitions in the hydrogen spectmm they are named after their discoverers. The Balmer series was particularly easy to study because a number of its lines fall in the visible range. 

---