Polarity and Intermolecular Forces

NonpolarPolar Diatomic molecules

NonpolarPolar Polyatomic molecules

Polar molecule or not? The shape of a molecule usually tells if a molecule is polar or not If the VSEPR shape is symmetric it is usually non-polar If the molecule is asymmetric it is polar

The force that exists between separate molecules. This force attracts molecules to each other. 3 types: – London dispersion – Dipole-dipole – Hydrogen bond Intermolecular forces

London dispersion Induced dipole between non polar molecules Weakest force (caused by the motion of electrons)

Dipole-dipole Attractive forces between polar molecules Stronger force than dispersion

Hydrogen Bond Forms between the hydrogen and the fluorine, oxygen, or nitrogen (FON) Strongest force of the three

IMF’s ALL molecules have dispersion forces All polar molecules have dipole-dipole forces and dispersion forces Molecules that H-bond have all 3 forces

Solubility of polar molecules Properties are due to intermolecular forces Like dissolves like -Polar substances will dissolve polar molecules -Non polar substances will dissolve non- polar molecules