135 articles
Bonding & Molecular Structure
Ionic, covalent and metallic bonds, molecular shapes, intermolecular forces and naming compounds.
Hydrogen Bonds vs Covalent Bonds: Strength, Length and Role
A side-by-side look at hydrogen bonds and covalent bonds: energies, lengths, what breaks when water boils, and when each one controls a property.
Hydrogen Bonding Misconceptions
Eight hydrogen bonding myths corrected: that any H atom can do it, that it's a covalent bond, that ice traps air, and why water out-boils HF.
Intermolecular Force Myths: What Boiling Really Breaks
Eight intermolecular force myths corrected: boiling breaks bonds, London forces are always weakest, heavier always means higher boiling, and more.
Lewis Structure of Ozone (O₃) and Resonance, Worked Step by Step
Work out ozone's Lewis structure, formal charges, resonance forms, bond order and bent shape, then compare O₃ with NO₂⁻ and SO₂ in six worked problems.
Lewis Structures of Polyatomic Ions: 6 Worked Examples
Draw Lewis structures for OH⁻, NH₄⁺, CN⁻, NO₂⁻, CO₃²⁻ and SO₄²⁻ step by step: electron counts for charged species, brackets, formal charges and resonance.
Investigating Melting Points and Bond Types
A safe practical using a water bath and melting-point apparatus to compare wax, stearic acid, sugar, salt and sand, then link each result to its bonding.
Molecular Polarity Practice Questions with Answers
14 exam-style questions on polar and non-polar molecules: bond dipoles, shape and symmetry, from CO₂ and H₂O to XeF₄, NF₃, ozone and dichloroethene.
All 13 VSEPR Shapes with Examples
Every common VSEPR shape from linear to square planar: electron domains, bonding and lone pairs, AXₙEₘ notation, bond angles and a real molecule for each.
Sodium Chloride vs Magnesium Oxide: Why MgO Melts So Much Higher
NaCl and MgO share the same rock-salt structure, yet MgO melts about 2,000 °C higher. Ion charge and ion size explain the gap, side by side.
Resonance Structures Practice: 14 Questions with Answers
Resonance practice from nitrite and carbonate to amides, enolates and phenoxide: drawing valid forms, bond orders, major vs minor contributors, full answers.
Sigma vs Pi Bonds Side by Side
Sigma and pi bonds compared: how the orbitals overlap, where the electrons sit, bond strength, rotation, reactivity and how to count them in any molecule.
sp, sp² and sp³ Hybridisation Compared
sp, sp² and sp³ carbon compared side by side: bond angles, shapes, s character, bond lengths, C–H acidity and how to spot each type quickly in an exam.
Teaching Intermolecular Forces: A Lesson Guide
A teaching guide to intermolecular forces: a three-lesson plan with timings, safe demos, boiling-point data tasks, misconceptions to expect, differentiation and questions.
Teaching Molecular Shapes with VSEPR
A VSEPR teaching guide: lesson timings, balloon and model-kit activities, the misconceptions students bring (flat drawings, ignored lone pairs) and graded questions.
Alloys: Why Mixing Metals Makes Them Stronger
What alloys are, substitutional vs interstitial alloys, why different-sized atoms stop layers sliding, and the chemistry of steel, bronze, brass, solder, duralumin, gold alloys and shape-memory metals.
Ranking Boiling Points Using Intermolecular Forces
A step-by-step method for ranking boiling points, with seven worked examples covering hydrocarbons, isomers, alcohols vs ethers, halogens, hydrides, ionic and covalent substances.
Bond Angles: Why Water Is Bent at 104.5°
Why bond angles take the values they do: electron-pair repulsion, lone pairs, electronegativity, atom size and multiple bonds — explained through water, ammonia, methane and more.
Bond Enthalpy Calculations with Worked Examples
Six fully worked bond enthalpy calculations — from hydrogen and chlorine to combustion of methane and ethanol, a reverse calculation and a comparison with Hess's law data.
Bond Length and Bond Strength: How They Relate
What bond length and bond strength (bond enthalpy) mean, how they're measured, why shorter bonds are usually stronger, the trends down a group and across bond orders, and the exceptions.
Bond Polarity: Using Electronegativity Differences
How to decide whether a bond is non-polar, polar covalent or ionic using Pauling electronegativity differences, with partial charges, worked examples, percent ionic character and effects.
Chemical Bonding Misconceptions (Including "Breaking Bonds Releases Energy")
Ten stubborn chemical bonding misconceptions — breaking bonds releases energy, atoms want full shells, NaCl molecules, boiling breaks bonds and more — each corrected with the real chemistry.
Dative (Coordinate) Covalent Bonds Explained
What a dative covalent bond is, how to recognise and draw one, and key examples: ammonium, hydronium, NH₃BF₃, aluminium chloride dimers, carbon monoxide and metal complexes.
Counting Sigma and Pi Bonds in Molecules
Worked examples for counting σ and π bonds — from ethene and CO₂ to benzene, aspirin and caffeine — with a fast method, a formula-based shortcut and common traps.
How to Determine the Hybridisation of Any Atom
A reliable step-by-step method for finding the hybridisation of any atom — count sigma bonds and lone pairs — with 12 worked examples and the tricky cases involving resonance.
Dipole–Dipole Forces Explained
How permanent dipole–dipole forces arise between polar molecules, how they compare with London forces and hydrogen bonds, worked boiling-point comparisons, and where they matter.
Dipole Moments: Why Some Molecules Are Polar
What a dipole moment is, how it's calculated and measured in debyes, how bond dipoles add as vectors, why shape decides polarity, and how dipole moments affect boiling points and solubility.
Electron Geometry vs Molecular Geometry
The difference between electron-domain geometry and molecular shape, with a complete comparison table, worked examples from CH₄ to XeF₄, and the most common exam mistakes.
How to Calculate Formal Charge (and Pick the Best Lewis Structure)
Step-by-step method for formal charge, with worked examples for CO₂, SCN⁻, NH₄⁺, CO, SO₄²⁻ and N₂O, the rules for choosing the best Lewis structure, and common mistakes.
Giant Covalent Structures: Diamond, Graphite and Silica
How diamond, graphite, graphene and silicon dioxide are built, and how their networks of covalent bonds explain their hardness, melting points, conductivity and uses.
Hybridisation: sp, sp2 and sp3 Orbitals Explained
Why carbon forms four equal bonds: the idea of hybrid orbitals, sp³, sp² and sp hybridisation with methane, ethene and ethyne, lone pairs in NH₃ and H₂O, and the limits of the model.