Intermolecular Bonding

Properties of Intermolecular Bonding

• Intermolecular forces are attractions that occur between molecules. Apparently weaker than ionic or covalent bonds.
• Three main types of intermolecular forces include London dispersion forces, dipole-dipole forces, and hydrogen bonding.

London Dispersion Forces

• These are temporary attractive forces that result when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.
• Instantaneous dipole-induced dipole bonds are the weakest type of intermolecular bond and occur between all atoms and molecules.
• These forces are the weakest intermolecular force and their strength increases with the number of electrons present.

Dipole-Dipole Forces

• These attractions occur between polar molecules orientated so that the positive and negative ends are close to each other.
• The positive end of a polar molecule is attracted to the negative end of another polar molecule.

Hydrogen Bonding

• This type exists when a hydrogen atom bonded to a highly electronegative atom exists near another electronegative atom with a lone pair of electrons.
• Hydrogen bonds are usually stronger than dipole-dipole and dispersion forces, but weaker than ionic or covalent bonds.
• Water is an example of a molecule with strong hydrogen bonds.

Remember, the polarity of a molecule and the intermolecular bonds it can form significantly affect its properties, such as boiling and melting points, surface tension, and solubility.