The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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All matter radiates electromagnetic energy when it is heated. Because each element is different, the radiation it emits under conditions of heating is unique and characteristic of that element. Line emission spectra, produced by heating a very hot gas under pressure, consists of a series of bright lines separated by dark regions. Each of the lines in a spectral series corresponds to a characteristic frequency or wavelength.
Ordinary atomic optical spectra suggest that the motion of the electrons in the outer part of an atom depend as much on the interactions between the electrons as on the attractive forces between the electrons and the atomic nucleus, both forces being of about the same magnitude. In 1890, the Swedish spectroscopist Johannes Rydberg (1854- 1919) identified a general relationship between the spectra of hydrogen and those of many other atoms. This relationship demonstrated the similarity of the spectral lines of elements with larger atomic numbers to the hydrogen spectral series.
Mathematically, Rydberg showed that the spectral terms in different spectral series can be represented by a formula. This formula contains a term which also appears in the mathematical representation predicting the characteristic wavelengths of some lines in the hydrogen spectrum. This common term is known as the Rydberg constant; it's value (for wavelength measured in meters) is 1.097 x 107/m.
Because Rydberg's formula includes a term characteristic of the hydrogen spectra, the formula has been interpreted to mean that the spectra that obey it are representative of the last step of a process by which a neutral atom is built up by capturing and binding electrons to a nucleus, one at a time. That is to say, the force that is required to bind an electron to a nucleus shielded by previously bound electrons is very similar to the force experienced by an electron from the nucleus of a hydrogen atom when the electron is the same distance from the nucleus as in the shielded case.