December 17, 2013
Bond polarity and polar molecules
How do you know if a bond is polar?
December 17, 2013
Bond polarity and polar molecules
How do you know if a bond is polar?
December 17, 2013
Bond polarity
• the greater the difference in electronegativity of two
atoms in a bond, the greater the polarity of the
bond.
> imbalance of charge distribution
> expressed with a dipole arrow
> bond strength increases with polarity
H-F
Practice:
Draw the dipole arrow for the following bonds:
N-N
S-O
C-Cl
C-O
N-C
Xe-F
December 17, 2013
Polar molecules
Molecules can be polar or nonpolar. It depends on:
1. Polarity of bonds
2. Geometry of molecule
*The molecule must have a net dipole moment
Polar molecules...
• have a partial negative charge on one side and a
partial positive charge on the other side
• align with an electric field
December 17, 2013
Molecular Polarity
December 17, 2013
Example:
CCl4
H2O
NH3
CH3Cl
BeF2
CH2F2