Lewis Symbols, Octet Rule and Bond Formation
Valence electrons provide the accounting language for ionic and covalent bonding.
Do not count all electrons in the atoms; Lewis structures use valence electrons.Free lesson · No login required
Chemical Bonding and Molecular Structure
Build molecular structure from valence electrons, then connect shape, bonding, polarity, bond order and intermolecular forces to observable properties.
Build the idea before the question
Ionic Bonding and Lattice Enthalpy
Ion formation and lattice stabilisation together determine whether an ionic arrangement is favourable.
Compare both ionic charge and size; charge alone is not the complete electrostatic picture.Bond Parameters, Polarity and Resonance
Bond length, strength, order, polarity and resonance describe different aspects of bonding.
Do not decide molecular polarity from one bond without considering geometry.Lewis Structures and Formal Charge
A disciplined electron-accounting method prevents incomplete or impossible structures.
Count half of all bonding electrons assigned to the atom, not the number of bonds twice.VSEPR Shape Explorer
Change the species and observe how electron domains determine shape, hybridisation and polarity.
Electron geometry
Molecular shape
Hybridisation
Electron counting and bond order
Lewis Structure Builder
Bond Order & Magnetism
Try KCET-style questions with nudges
1. How many valence electrons are present in one CO₂ molecule?
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Count only outer-shell electrons.
Explanation: One carbon and two oxygen atoms contribute 4 + 12 = 16 valence electrons.
2. Which molecule has an electron-deficient central atom in its usual Lewis structure?
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Look for a Group 13 central atom.
Explanation: BF₃ is a standard incomplete-octet exception; boron has only six surrounding electrons.
3. Which compound is expected to have the larger lattice-enthalpy magnitude?
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Compare ionic charge products first.
Explanation: The doubly charged, compact ions in MgO give much stronger electrostatic attraction.
4. Which cation most strongly polarises the same anion?
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Polarising power rises with charge density.
Explanation: Al³⁺ distorts an anion electron cloud most strongly and therefore increases covalent character most.
5. Which carbon–carbon bond is shortest?
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Compare bond orders.
Explanation: A C≡C bond is shorter and generally stronger than C=C and C–C bonds.
6. Why is CO₂ non-polar although each C=O bond is polar?
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Molecular dipole moment is a vector sum.
Explanation: Linear symmetry makes the two polar bond moments cancel exactly.
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