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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A cation is a positively charged ion. The name comes from a 19th century combination of cata (from the Greek for down, kata) and ion. During electrolysis, cations are reduced at the cathode.
Cations have all lost one or more electrons, giving them a net positive charge. Thus, cations have more protons than electrons. Monatomic (single atom) cations are typically either metallic elements or hydrogen. This is because these are the elements with a tendency to lose electrons in a reaction, making them positively charged. Cations can, however, also be positively charged groups of atoms (polyatomic cations) such as ammonium NH4. In nature, cations cannot exist by themselves. They are always in the presence of anions (negative ions). Cations and anions can only exist in ionic compounds, nearly all of which are solids at room temperature, or in solution. A cation will form an ionic bond with an anion. In an ionic compound, the sum of the positive charge(s) of the cation(s) and the negative charge(s) of the anion(s)must be zero. The actual formula of the ionic compound (and the number of cations and anions) will thus depend on the relative charges of the anion and cation. The charge on a cation is typically +1, +2, or +3. The majority of metals have a cation with a +2 charge, although some can exist in different forms. For example, iron exists as both a +2 and a +3 cation. The characteristics of the +2 and +3 form are slightly different. Iron nitrate can be found as iron (II) nitrate or iron (III) nitrate, the former being green in color while the latter is pale violet.