Chemistry study notes
Chemical Bonding
Explain particles, molecular shape and material properties through electrostatic attraction.
A-Level 8873, revised syllabus (2026-2027)
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Learning outcomes and sources
2. Chemical Bonding (8873, 2026 revision; examinations 2026 and 2027). Use the outcome map to find the explanation for a particular syllabus requirement.
See the learning outcome map
2(a) Explain the electrostatic basis of bonding.
- (i) Ionic: opposite ions.
- (ii) Covalent: shared pair and positive nuclei.
- (iii) Metallic: positive lattice and delocalised electrons.
2(b) Explain bonding using electron diagrams.
- (i) NaCl and MgO.
- (ii) H2, O2, N2, Cl2, HCl, CO2, CH4 and ethene.
- (iii) Dative bonding in NH4+ formation and Al2Cl6.
One idea behind three strong bondsMake every electron countWhen one atom supplies the shared pair
2(c) Connect overlap to sigma and pi bonds.
- s and p orbital overlap only; connection to organic shapes.
2(d) Explain the required shapes with VSEPR.
- BF3 120; CO2 180; CH4 109.5; NH3 about 107; H2O about 104.5; SF6 90/180 degrees.
2(e) Predict analogous shapes and angles.
- Count bonding domains and lone pairs; apply the listed geometries.
2(f) Infer bond polarity.
- Electronegativity; qualitative treatment, not numerical calculations.
2(g) Infer molecular polarity.
- Combine bond dipoles with shapes analogous to 2(d).
2(h) Explain intermolecular attractions.
- (i) Permanent and induced dipoles in CHCl3, Br2 and noble gases, liquid/gas.
- (ii) Hydrogen bonding in NH3 and H2O; N-H and O-H groups.
2(i) Explain gas liquefaction.
- High pressure and/or low temperature make intermolecular attractions important.
2(j) Connect hydrogen bonding to properties.
- Water boiling behaviour and open ice structure/density.
2(k) Explain bond energy and length.
- Covalent bonds; gaseous bond breaking and equilibrium internuclear separation.
2(l) Compare covalent bond reactivity.
- Bond energy, length and polarity; use comparable reaction contexts.
2(m) Describe crystalline lattice types.
- (i) NaCl/MgO ionic.
- (ii) Iodine molecular.
- (iii) Diamond/graphite giant molecular.
- (iv) Ice hydrogen-bonded.
- (v) Copper metallic; no unit cells.
2(n) Predict physical properties from structure.
- Melting, conductivity, mechanical behaviour and qualified solubility reasoning.
2(o) Infer structure from properties.
- Combine evidence; distinguish mobile ions from electrons.
- SEAB H1 Chemistry 8873, 2026 revision
Official scope: section 2, printed pages 12-13. All lettered outcomes and nested requirements checked.
- SEAB H1 Chemistry 8873, 2027
Section 2: same substantive outcomes as the revised 2026 course.
- NJC 5 Chemical Bonding (H1) (Grail)
Consulted printed pp. 29-31 for electron-region to molecular-shape reasoning and pp. 37-38 for hydrogen bonding. Added an original SCl2 electron-accounting deduction; did not adopt a fixed angle decrement per lone pair or a universal bond-strength ranking.