Between the Extremes Electronegativity and Bond Polarity

Now look at a case in which the two atoms have extremely different electronegativities — sodium chloride (NaCl). Sodium chloride is ionically bonded (see Chapter 6 for information on ionic bonds). An electron has transferred from sodium to chlorine. Sodium has an electronegativity of 1.0, and chlorine has an electronegativity of 3.0. That s an electronegativity difference of 2.0 (3.0 - 1.0), making the bond between the two atoms very, very polar. In fact, the electronegativity difference provides another way of predicting the kind of bond that will form between two elements. 

Polar covalent bonds are covalent bonds with ionic character (partial election transfer). Ionic and covalent bonding are extremes forms of bonding polar bonds are intermediate in nature. The larger the difference in electronegativity between the atoms, the greater the polarity of the... 

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