Bonding, Shape and Polarity
Ionic, covalent, coordinate and metallic bonding, electronegativity, bond polarity, electron-pair repulsion and molecular shape.
How to study A-level Chemistry
Represent the species and process correctly, conserve atoms, charge and energy, calculate with units, then test the result against observations and chemical evidence.
Core concepts
Concept 1
Bond models describe electrostatic attraction between appropriate charged particles or shared electron density.
Exam cue: Count bonding pairs and lone pairs around the central atom before naming shape and angle.
Concept 2
Electron-pair repulsion predicts shape, with lone pairs exerting stronger repulsion than bonding pairs.
Exam cue: Distinguish a polar bond from an overall polar molecule.
Concept 3
Molecular polarity depends on bond polarities and their three-dimensional arrangement.
Exam cue: Describe the particles and attractive force rather than saying atoms want full shells.
Risk pitfalls and guardrails
Treating covalent bonds as intermolecular forces.
Guardrail: Do not substitute a memorised equation, mechanism or trend until you have identified the species, conditions and chemical model required.
Ignoring lone pairs when predicting bond angle.
Guardrail: Do not substitute a memorised equation, mechanism or trend until you have identified the species, conditions and chemical model required.
Assuming every molecule containing polar bonds has a permanent dipole.
Guardrail: Do not substitute a memorised equation, mechanism or trend until you have identified the species, conditions and chemical model required.
Memory anchors
Ionic Bonding
Ionic bonding is electrostatic attraction between oppositely charged ions.
Covalent Bond
A covalent bond is electrostatic attraction between nuclei and a shared pair of electrons.
Coordinate Bond
A coordinate bond is a covalent bond whose shared pair comes from one atom.
Electronegativity
Electronegativity is an atom's ability to attract the bonding pair in a covalent bond.
Lone-pair Repulsion
Lone pairs repel more strongly than bonding pairs and reduce adjacent bond angles.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
What type of bonding holds Na⁺ and Cl⁻ ions together in solid sodium chloride?
Which statement best describes a covalent bond?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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