This slideshow provides a brief overview of molecular polarity and dipole-dipole forces in chemistry. With easy-to-understand examples and visual representations, your understanding of polarity and intermolecular forces should improve drastically.

1. Molecular Polarity and
Dipole-Dipole Forces
A CHEMISTRY PRESENTATION

2. Intermolecular Forces
• the strongest intermolecular forces exist between polar
molecules
– polar molecules act as dipoles
– these dipoles are short range
– they have equal but opposite charges
– positive to negative poles (the arrow’s head points towards
the more electronegative of the two atoms in the bond)
EX. H Cl

3. Dipole-Dipole Forces
• dipole-dipole – attraction between polar molecules
• polar molecules have greater boiling points than
nonpolar molecules
– this is because nonpolar molecules are held together by
weaker forces, called van der Waals forces
– since the dipole-dipole forces that hold polar molecules
together are stronger than van der Waals forces, it is harder
for their bonds to be broken by a boiling liquid

4. Dipole-Dipole Forces Cont.
• polar molecules have a partially charged positive end
and a partially charged negative end
• polar molecules can also induce a dipole in nonpolar
molecules because polar molecules can temporarily act
as electrons
– however, these dipoles are weaker than dipole-dipole forces

5. What Do Dipole-Dipole Forces
Look Like?
the idea of “opposites attract” may not be applicable to
real life relationships, but in dipole-dipole forces, this is the
basic principle
!
!
in this figure, the dipole-dipole forces that exist between
atoms in the chemical compound iodine monochloride are
set up in a way where the negative and positive poles are
connected, not negative-negative or positive-positive

6. But Why do Opposites Attract?
• in dipole-dipole interactions, both ends of the pole (“di”
means two, so “dipole” means two ends of one pole)
have partial charges
– the two “complete” each other, resulting in a neutral charge

7. References
• Modern Chemistry – Holt, Rinehart, and Winston
• https://www.chem.purdue.edu/gchelp/liquids/dipdip.html