How are electronegativity values used?
Consider coupling two fluorine atoms together. Even though each atom has a high attraction for bonding electrons, both attract them equally. (We’ve got two well-matched Boston Terriers pulling on this sock.) The electronegativity difference between the atoms is zero, and the bond is pure covalent. The electron distribution around the fluorine atoms is shown at right. Coupling fluorine to oxygen (in F2O, for example) results in a bond that is polarized. Bonding electrons spend more time around the fluorine than the oxygen because fluorine has the higher electronegativity. The fluorine end of the bond has a partial negative charge, and the oxygen end has a partial positive charge. The bond has some ionic character. But the electronegativity difference is only 0.5, so the bonding electrons are shared, too. The bond is best described as polar covalent. (Think of a Boston Terrier pulling against a German Shepherd). Coupling fluorine to lithium results in a bond with a much larger electroneg
