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(ĭlĕk'trōnĕgətĭv`ətē), in chemistry, tendency for an atom to attract a pair of electrons that it shares with another atom (see chemical bondchemical bond,
mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the formation of an aggregate with sufficient stability to be regarded as an
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). For example, the molecule hydrogen chloride, HCl, consists of a hydrogen atom, H, and a chlorine atom, Cl, sharing a pair of electrons. If the pair of electrons are not shared equally, i.e., if they spend more time with one atom than with the other, the favored atom is said to be more electronegative. In the case of HCl, measurements indicate that the molecule has a dipole moment, that is, the chlorine end is relatively negative and the hydrogen end is relatively positive. This means that the electron pair spends more time with the chlorine atom than with the hydrogen atom and thus chlorine is more electronegative than hydrogen. Nonmetals have much higher electronegativities than metals; of the nonmetals, fluorine is the most electronegative, followed by oxygen, nitrogen, and chlorine. The larger the difference in electronegativity between two atoms, the more polar the bond between them. In the extreme case of a bond between a metal and a nonmetal, a complete transfer of electrons takes place.



a quantity that characterizes the power of an atom in a molecule to attract electrons that take part in the formation of chemical bonds. Several methods have been developed for the calculation of electronegativity. For example, in 1935, R. Mulliken suggested that the sum of an atom’s ionization potential and electron affinity could serve as a measure of the atom’s electronegativity. In 1932, L. Pauling proposed another, more complicated method (seeCHEMICAL BOND). However, all the known methods turn out to yield virtually identical results.

If electronegativities are known, the electron density distribution in the molecules of many chemical substances may be approximately estimated. For example, the polarity of a covalent bond can be determined.

References in periodicals archive ?
The topics include dipole moment as a possible diagnostic descriptor of the conformational isomerism of the ammonia molecule, commonality in the origin of electronegativity and hardness and their manifestation in the real world, the biological synthesis of silver nanoparticles and their functional properties, modeling carbon nanotubes as drug delivery nanocapsules, and a method for determining the global hardness of atoms and molecules.
Electronegativity can be used effectively as an integrative core concept to assist student understanding of chemical principles.
2]O, which they claim is possible because of the high electronegativity of the C1 and O.
Surface charge of each was determined in order to relate electronegativity with biosorption capacity.
Fluorinated copolymers are known to have many useful and desirable features, such as high thermal, aging, and weather resistance; excellent inertness to solvents, acids, and alkalis; and oil and water repellency due to the low polarizability and the strong electronegativity of the fluorine atom.
Due to the electronegativity of oxygen the electron density of the Si-H bond in trimethoxysilane is localized on silicon, thus loosening hydrogen and making the alkoxy compound more reactive.
There were plenty of quantum mechanical calculations and determinations of ionization potentials and studies of trends in electronegativity to keep me burning the midnight oil.
It has been shown that the difference in electronegativity of the heteroatoms (oxygen, hydrogen, and nitrogen) relative to the C atom gives torrefied and pyrolysed biomass its surface chemical heterogeneity (Brennan et al.
Electronegativity is a measure of an element's ability to attract or hold onto electrons.
A change in the area of activation or a decrease in surface electronegativity suggests functional reorganization of the cortex and a lesser requirement of cortical activation as a motor skill becomes more automatic.
Forming these alloys has been limited to elements close in atomic radii and electronegativity up until now," said Professor Rajeev Ahuja of UU.