Atoms spectra

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. 

Hund s rule, like the Pauli exclusion principle, is based on experiment It is possible to determine the number of unpaired electrons in an atom. With solids, this is done by studying their behavior in a magnetic field. If there are unpaired electrons present the solid will be attracted into the field. Such a substance is said to be paramagnetic. If the atoms in the solid contain only paired electrons, it is slightly repelled by the field. Substances of this type are called diamagnetic. With gaseous atoms, the atomic spectrum can also be used to establish the presence and number of unpaired electrons. 

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

Wavelength (A) A characteristic property of a wave related to its color and equal to the length of a full wave, 133 atomic spectrum of hydrogen, 136 color and, 17t... 

Pto/e / I7. The hydrogen atom spectrum a clue to energy levels. 

This splitting of the energy levels by the magnetic field leads to the splitting of the lines in the atomic spectrum. The wave number v of the spectral line corresponding to a transition between the state /i mi) and the state nihm2) is... 

The atomic spectrum of singly ionized helium He+ with i = 4, 2 = 5, 6,. .. is known as the Pickering series. Calculate the energy differences, wave numbers, and wavelengths for the first three lines in this spectrum and for the series limit. 

H atomic spectrum Calculation of the allowed transition frequencies in the... 

The spectrum of the Sun contains the absorption lines associated with the atomic spectrum of heavier elements such as Fe (Figure 4.2), which indicates that the Sun is a second-generation star formed from a stellar nebula containing many heavy nuclei. The atomic spectra of heavier atoms are more complex. The simple expression for the H atom spectrum needs to be modified to include a quantum defect but this is beyond the scope of this book. Atomic spectra are visible for all other elements in the same way as for H, including transitions in ionised species such as Ca2+ and Fe2+ (Figure 4.2). 

Figure 4.12 The origin of Zeeman splitting in the n = 2-n = 3 transition in the H atomic spectrum...

Lyman series The series of the hydrogen atom spectrum with n = 1 as the starting level. 

Hi) Line Spectra Line spectra are usually encountered when the light emitting substance i.e., the radiating species are separate atomic entities (particles) which are distinctly separated from one another, as in gas. Therefore, it is invariably known as atomic spectrum . As the line spectrum depends solely upon the type of an atom, hence it enjoys the status of a predominant type of emission spectroscopy. 

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

Indium (In, [Kr]4 /I05.v25/ 1), name and symbol after the indigo line in its atomic spectrum. Discovered (1863) by Ferdinand Reich and Hieronymus Theodor Richter. Silvery lustrous grey, very soft metal. 

Increasing the temperature causes dissociation of the CuCI molecules into neutral atoms which, in turn, emit an atomic spectrum composed of atomic (arc) lines. In this state, one of two things can occur. The atoms can combine with hydroxide radicals (charge carrying radical symbol OH species commonly found in flames) or oxygen atoms to form CuOH or CuO. These gaseous molecules emit a band spectrum and behave like CuCI. 

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