Polar Bonds and
Molecules
Chapter 8.4
Learning Objectives
• Be able to use electronegativity to identify polar
vs. non-polar covalent bond
• Draw correct dipoles on a covalent bond
• Draw correct net dipole on a molecular compound
If the difference in
electronegativity is between
–
–
–
1.7 to 4.0: Ionic Bond
0.3 to 1.7: Polar Covalent Bond
0.0 to 0.3: Non-Polar Covalent Bond
Electronegativity Scale
Polar Covalent Bond vs NonPolar Covalent Bond
Polar Covalent vs Non-Polar
Covalent
Drawing Bond Dipoles: BF3
Drawing Bond Dipoles: CH3OH
Net Dipole of Molecules
Dipole – separation of charges within a molecule
between two covalently bonded atoms.
Net Dipole – When all the dipole vectors are
summed to give one overall dipole.
Let’s Practice
Get out your white boards …
Show the polar bonds (d- and d+) and then predict
the net dipole moment of the molecule. You’ll need
to use the electronegativity chart on page 177 of
your textbook.
PF3 - phosphorus trifluoride
NH3 - ammonia (nitrogen trihydride)
CCl4 – carbon tetrachloride
BrF5 - bromine pentafluoride