In
chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
, Abegg’s rule states that the difference between the maximum positive and negative
valence of an
element is frequently eight. The rule used a historic meaning of valence which resembles the modern concept of
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
in which an atom is an electron donor or receiver. Abegg’s rule is sometimes referred to as "Abegg’s law of valence and countervalence".
In general, for a given chemical element (as
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
) Abegg’s rule states that the sum of the absolute value of its negative valence (such as −2 for sulfur in
H2S and its positive valence of maximum value (as +6 for sulfur in
H2SO4) is often equal to 8.
History
The concept was formulated in 1904 by German chemist
Richard Abegg
Richard Wilhelm Heinrich Abegg (9 January 1869 – 3 April 1910) was a German chemist and pioneer of valence theory. He proposed that the difference of the maximum positive and negative valence of an element tends to be eight. This has come to be ...
.
Gilbert N. Lewis was one of the first to refer to the concept as "Abegg's rule" when he used it as a basis of argument in a 1916 article to develop his
cubical atom
The cubical atom was an early atomic model in which electrons were positioned at the eight corners of a cube in a non-polar atom or molecule. This theory was developed in 1902 by Gilbert N. Lewis and published in 1916 in the article "The Atom and ...
theory, which developed into the
octet rule
The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas. The rule i ...
. That article helped inspire
Linus Pauling
Linus Carl Pauling (; February 28, 1901August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific top ...
to write his 1938 textbook ''The Nature of the Chemical Bond''.
See also
*
History of molecular theory
*
Irving Langmuir
Irving Langmuir (; January 31, 1881 – August 16, 1957) was an American chemist, physicist, and engineer. He was awarded the Nobel Prize in Chemistry in 1932 for his work in surface chemistry.
Langmuir's most famous publication is the 1919 art ...
References
External links
Nuclear Atom- contains and excerpt of Abegg's contributions.
Chemistry theories
Theoretical chemistry
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