Electrostatic effects on the properties of organic compounds are reviewed to demonstrate the importance of electronegativity differences between the atoms forming a bond. Bond dissociation energies are generally found to increase as the electronegativity difference increases, and the bonds have increased ionic character. The stabilization of polyfluorinated compounds arises in a similar fashion, with the positive charge at carbon increasing linearly with the number of fluorines. The carbonyl group is strongly polarized, and substituents that take electron density from the carbon will lead to a stronger electrostatic interaction in the carbonyl group, resulting in a decrease in energy. The application of these ideas to amide resonance, the acidity of carboxylic acids and substituent effects at vinyl groups are discussed.