Polar Bonds and Molecules (8.4)

1. Polar Bonds and Molecules (8.4) • Bond Polarity • Bond polarity has to do with unequal distribution of shared electrons • This causes one end of the bond to have a “partial positive” (δ+) charge and the other to have a “partial negative” (δ-)charge • These types of bonds are called polar covalent bonds and are said to possess a dipole moment

2. What causes bond polarity? • A polar bond results from a difference in electronegativity between the bonded atoms • The greater the difference, the more polar the bond is • The degree of polarity depends upon the difference in electronegativity

3. Electronegativity Differences and Bond Types (Bond Character)

4. Effect of Bond Polarity on Molecules • Polar bonds may result in polar molecules • Bond character (nonpolar, polar, ionic) affects • How molecules interact with one another • Physical properties of substances

5. Polarity of Molecules • A molecule as a whole has a dipole depending upon • The presence of polar bond(s) • The geometry of a molecule • Examples: • CH4 • CO2 • H2O