Electronegativity

Adapted from Wikipedia

Electronegativity is a measure of the attractive potential of an atom or molecule to electrons within a chemical bond. The "type" of bond observed is largely determined by the difference in electronegativity between the atoms involved in making the bond. Atoms with similar electronegativities will share an electron with each other and form a covalent bond (e.g. the carbon-hydrogen bonds in methane). However, if the difference is too great, the electron will be permanently transferred to one atom and an ionic bond will form (e.g. sodium chloride ions in common salt). Furthermore, in a covalent bond if one atom pulls slightly harder than the other a polar covalent bond will form (e.g. the oxygen-hydrogen bond in water).

The converse of electronegativity, the ability of an atom to lose electrons, is known as electropositivity. Scientists commonly use two different scales of electronegativity: the Pauling scale (proposed in 1932) and the Mulliken scale (proposed in 1934). Another proposal is the Allred-Rochow scale.

 

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