3.6 Intermolecular Forces
Use this landing page to move between the six intermolecular forces revision pages for Cambridge International AS Level Chemistry Topic 3. Each card links to a focused page covering part of learning outcomes 3.6.1 to 3.6.4.
Choose an Intermolecular Forces Page
Cambridge uses van der Waals’ forces as the family name for the attractions between molecules, then divides them into instantaneous dipole-induced dipole forces and permanent dipole-permanent dipole forces, with hydrogen bonding as a special case. These pages cover all three, the anomalous properties of water including surface tension, boiling point trends and the choice of solvent.
Key idea: Intermolecular forces act between molecules and are far weaker than the covalent bonds inside them; when a molecular substance melts or boils, only these forces are overcome.
London Forces
Revise how moving electrons create instantaneous and induced dipoles, and why electrons and shape decide their strength.
Start revisingPermanent Dipole-Dipole Forces
Revise which molecules have a permanent dipole, how they attract, and how to decide the forces in an unfamiliar molecule.
Start revisingHydrogen Bonding
Revise the N-H, O-H and H-F requirement, the exam diagram, and predicting hydrogen bonding in other molecules.
Start revisingAnomalous Properties of Water
Revise why water has such a high boiling point, why ice floats and why water has a high surface tension.
Start revisingBoiling Point Trends
Revise boiling point trends for alkanes, branched isomers, alcohols and the hydrogen halides.
Start revisingChoosing Solvents
Revise hydration of ions, alcohols in water, why some polar molecules do not dissolve, and non-aqueous solvents.
Start revisingCopyright notice: This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.
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