Chapter summary
Chemical Bonding, at a glance
Use electrons, molecular shape and electrostatic attraction to explain structures, properties and reactivity.
A-Level 9476 (2026-2027)
Quick revision
Revisit the essentials, then return to an explanation when you need it.
| Term | Definition to write |
|---|---|
| Ionic bond | The electrostatic attraction between oppositely charged ions. |
| Covalent bond | The electrostatic attraction between a shared pair of electrons and the nuclei of the two bonded atoms. |
| Dative (coordinate) bond | A covalent bond in which both shared electrons come from the same atom. |
| Metallic bond | The electrostatic attraction between a lattice of positive metal ions and a sea of delocalised electrons. |
| Electronegativity | The ability of an atom in a molecule to attract the shared pair of electrons in a covalent bond towards itself. |
| Hydrogen bond | An attraction between an H atom bonded to N, O or F (so carrying a large δ+) and a lone pair on an N, O or F atom of a neighbouring molecule. |
- Name the particles and arrangement
Ions, atoms or molecules; discrete units, sheets or an extended network.
- Name the relevant attraction
Ionic, covalent, metallic or a specific intermolecular attraction.
- Connect to the observation
Energy to overcome attraction explains melting; mobile charges explain conductivity.
| Do not confuse | Reason |
|---|---|
| Bond polarity / molecular polarity | Dipoles may cancel by symmetry. |
| Covalent bond / intermolecular force | Melting a molecular solid does not break its molecules. |
| Sigma / pi | Double = 1 sigma + 1 pi; triple = 1 sigma + 2 pi. |
| Electron arrangement / molecular shape | Lone pairs count as regions but are omitted from the atom-based shape name. |
| Dative formation / finished bond | The donor supplies the pair; the finished bond is covalent. |
| Bond energy / reaction rate | The pathway and activation barrier also matter. |
Quick recall
How do sigma and pi bonds differ in the way they form?