Polar+and+nonpolar+covalent+bonds

Electronegativity is used to estimate a bond's polarity. Bond polarity is the sharing of electrons between atoms where as electronegativity is defined as the ability of an atom in a molecule to attract electrons to itself. The electronegativity of an atom in a molecule is related to its ionization energy and electron affinity. For example, an atom with a very negative electron affinity and high ionization energy will both attract electrons and resist having its electrons attracted away; it will be highly electronegative. Linus Pauling created a scale that shows the electronegativity for many of the elements. It ranges from .7 to 4.0.The trend for this is: Increases from left to right (with some transition metal exceptions), and decreases with increasing atomic number.
 * Electronegativity**

In these bonds, one of the atoms exerts a greater attraction for the bonding electrons than the other. A polar covalent bond results when the atoms differ in electronegativity. If the change in electronegativity of the bonded atoms is from .5 to 1.6, it is a polar covalent bond. In this bond, the higher electronegative atom pulls away some of the electron density from the nucleus of the other atom, making it slightly positive. This charge distribution is represented by delta plus/delta minus symbols.
 * Polar Covalent Bonds**



This bond has electrons that are shared equally between two atoms. A nonpolar covalent bond results when the electronegativities of the bonded atoms are equal.If the change in electronegativity of the bonded atoms is from 0 to .4, it is a nonpolar covalent bond.
 * Non-polar Covalent Bond**

If the difference in relative ability to attract electrons is large enough, an ionic bond is formed. If the change in electronegativity is higher than 1.7, it is then an ionic bond.
 * Key Concepts**

[|academic.brooklyn.cuny.edu/. ../page/polar_c.htm] [|chemsite.lsrhs.net/.../ electronegativity.html] [|www.bpreid.com/.../ ChemicalChange/3_bonding.htm] //Chemistry The Central Science, Ninth Edition//**
 * Sources