Chapter summary
Chemical Bonding, at a glance
Explain particles, molecular shape and material properties through electrostatic attraction.
A-Level 8873, revised syllabus (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. |
| 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. |
| Bond energy | The average energy required to break one mole of a particular covalent bond in gaseous molecules. |
| Bond length | The distance between the nuclei of two covalently bonded atoms. |
| 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. |
- Particles
Atoms, molecules, ions or ions with delocalised electrons?
- Attraction
Which electrostatic attraction holds the structure?
- Change
Which attraction is overcome, or which charge carrier moves?
- Conclusion
Link that mechanism directly to the measured property.
| Pair of ideas | Difference |
|---|---|
| Bond polarity / molecular polarity | Polar bonds may cancel through symmetry. |
| Sigma / pi | Head-on axial overlap / sideways p overlap. |
| Melting iodine / breaking I2 | Intermolecular separation / covalent bond breaking. |
| NH3 / NH4+ | Three bonds plus lone pair / four bonds, no lone pair. |
| Diamond / graphite | 3-D four-coordinate network / three-coordinate sheets with delocalised electrons. |
Quick recall
What is a dative (coordinate) bond? Give an example.