# Intermolecular Forces
4.4.NoS
Obtain evidence for scientific theories by making and testing predictions based on themāLondon (dispersion) forces and hydrogen bonding can be used to explain special interactions. For example, molecular covalent compounds can exist in the liquid and solid states. To explain this, there must be attractive forces between their particles which are significantly greater than those that could be attributed to gravity. (2.2)
4.4.U1
Intermolecular forces include London (dispersion) forces, dipole-dipole forces and hydrogen bonding.
4.4.U2
The relative strengths of these interactions are London (dispersion) forces < dipole-dipole forces < hydrogen bonds.
4.4.AS1
Deduction of the types of intermolecular force present in substances, based on their structure and chemical formula.
4.4.AS2
Explanation of the physical properties of covalent compounds (volatility, electrical conductivity and solubility) in terms of their structure and intermolecular forces.
4.4.G1
The term āLondon (dispersion) forcesā refers to instantaneous induced dipole- induced dipole forces that exist between any atoms or groups of atoms and should be used for non-polar entities. The term āvan der Waalsā is an inclusive term, which includes dipoleādipole, dipole-induced dipole and London (dispersion) forces.
4.4.ToK1
The nature of the hydrogen bond is the topic of much discussion and the current definition from the IUPAC gives six criteria which should be used as evidence for the occurrence of hydrogen bonding. How does a specialized vocabulary help and hinder the growth of knowledge?
4.4.Aims1
Aim 7: Computer simulations could be used to show intermolecular forces interactions.