Molecular Polarity & Intermolecular Bonds

INTERMOLECULAR: intermolecular means the bonds are outside of the molecule

A. Polarity is the result of intermolecular bonds.
1) London Dispersion Force

• experience by all molecules
• results of electrons pushing on each other
• the weakest of all forces
• As the number of electrons increase LDF increases also

2)Dipole-Dipole

• Dipoles are partial separation of charges
• LDF is a type of temporary dipole
• Some molecules have a permanent dipole
• These are polar molecules
• Polarity is determined by electron affinity(how much an atom wants electrons)
• Electron affinity is called electron negativity
• Electron negativity is highest on the top right and lowest on the bottom left

• A bond between two atoms or molecules with different electron negativites result in a dipole-dipole bond.
• Dipole-dipole forces are weak versions of ionic bonds

EXAMPLES:
CHCl3 is polar because: its structural model is not symmetrical so that means it is polar.
C2H2Cl2 is both polar and non-polar depending on how you draw the structural model