1. Molecular Polarity • A dipole is anything with a positive end and a negative end. Another word for dipole is polar. • A bond is a dipole (polar) if it connects different atoms. • A polar molecule (dipole) is a molecule where the polar bonds are asymmetrically (not symmetrically) arranged (the dipoles do not cancel). • A nonpolar molecule is a molecule with no polar bonds or a molecule where the polar bonds are symmetrically arranged (the dipoles cancel).

2. The dipole moment is the measurement of a molecules polarity. Arrow points toward the more electronegative atom. H Cl Dipole Moment - +

3. O net dipole moment H2O H H Determining Molecular Polarity • Polar Molecule • Dipoles (Polar Bonds) are asymmetrically arranged and don’t cancel in this bent (angular) molecule.

4. H ent CHCl3 Cl Cl Cl Determining Molecular Polarity • Therefore, polar molecules have... • asymmetrical charge distribution resulting in a positive and negative end to the molecule and a net dipole moment.The dipoles don’t cancel Net dipole moment

5. F BF3 B F F Determining Molecular Polarity • Nonpolar Molecules • Dipoles (Polar Bonds) are symmetrically arranged and cancel out in this trigonal planar shaped molecule.