Hydrogen atom, emission spectrum

In 1913 Bohr amalgamated classical and quantum mechanics in explaining the observation of not only the Balmer series but also the Lyman, Paschen, Brackett, Pfund, etc., series in the hydrogen atom emission spectrum, illustrated in Figure 1.1. Bohr assumed empirically that the electron can move only in specific circular orbits around the nucleus and that the angular momentum pe for an angle of rotation 9 is given by... 

Figure 5.8 shows an illustration of the characteristic purple-pink glow produced by excited hydrogen atoms and the visible portion of hydrogen s emission spectrum responsible for producing the glow. Note how the line nature of hydrogens atomic emission spectrum differs from that of a continuous spectrum. 

The dual wave-particle model of light accounted for several previously unexplainable phenomena, but scientists still did not understand the relationships among atomic structure, electrons, and atomic emission spectra. Recall that hydrogens atomic emission spectrum is discontinuous that is, it is made up of only certain frequencies of light. Why are the atomic emission spectra of elements discontinuous rather than continuous Niels Bohr, a Danish physicist working in Rutherford s laboratory in 1913, proposed a quantum model for the hydrogen atom that seemed to answer this question. Bohr s model also correctly predicted the frequencies of the lines in hydrogens atomic emission spectrum. 

One of the lines in the Balmer series of the hydrogen atom emission spectrum is at 397 nm. It results from a transition from an upper energy level ton = 2. What is the principal quantum number of the upper level ... 

Figure 23.2 The Visible Portion of the Hydrogen Atom Emission Spectrum (Simulated). Each wavelength represented produces an image of the slit of the spectrograph. If only discrete wavelengths are present, as in this case, the spectrum is called a line spectrum.

Bohr s realization that the atom s energy is quantized—that electrons are restricted to specific energy levels (orbits)— was an astounding achievement. As you have seen, this model successfully predicted the coloured lines in the visible-light portion of hydrogen s emission spectrum. It also successfully predicted other lines, shown in Figure 3.11, that earlier chemists had discovered in the ultraviolet and infrared portions of hydrogen s emission spectrum. 

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. 

In 1913, the Danish physicist Niels Bohr developed a model of the atom that explained the hydrogen emission spectrum. In Bohr s model, electrons orbit the nucleus in the same way that Earth orbits the Sun, as shown in Figure D.2. The following three points of Bohr s theory help to explain hydrogen s emission spectrum. 

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 ... 

According to the Bohr model of the atom, hydrogen s atomic emission spectrum results from electrons dropping from higher-energy atomic orbits to lower-energy atomic orbits. 

Flame photometric detector FPD, a selective GC detector for sulphur and phosphorus containing compounds. Separated components pass into a hydrogen-rich flame where they undergo a series of reactions to produce excited species HPO and S2. The resulting atomic emission spectrum is monitored using narrow band pass filters (526 and 394 nm, respectively) and a photomultiplier detector, sensitivity is 10 to 10 " gs . ... 

Figure 5.8 The purple light emitted by hydrogen can be separated into its different components using a prism. Hydrogen has an atomic emission spectrum that comprises four lines of different wavelengths. 

Figure 5.12 shows that, unlike rungs on a ladder, however, the hydrogen atom s energy levels are not evenly spaced. Figure 5.12 also illustrates the four electron transitions that account for visible lines in hydrogen s atomic emission spectrum, shown in Figure 5.8. Electron transitions from higher-energy orbits to the second orbit account for all of hydrogen s visible lines, which form the Balmer series. Other electron transitions have been measured that are not visible, such as the Lyman series (ultraviolet), in which electrons drop into the n = I orbit, and the Paschen series (infrared), in which electrons drop into the n = 3 orbit.

What electron transitions account for the Balmer series Hydrogen s emission spectrum comprises three series of lines. Some wavelengths are ultraviolet (Lyman series) and infrared (Paschen series). Visible wavelengths comprise the Balmer series. The Bohr atomic model attributes these spectral lines to transitions from higher-energy states with electron orbits in which n = n, to lower-energy states with smaller electron orbits in which n = nf. 

I Bohr s atomic model attributes hydrogen s emission spectrum to electrons dropping from higher-energy to lower-energy orbits. 

In Bohr s atomic model, what electron-orbit transition produces the blue-green line in hydrogen s atomic emission spectrum ... 

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