135 articles
Bonding & Molecular Structure
Ionic, covalent and metallic bonds, molecular shapes, intermolecular forces and naming compounds.
Properties of Ionic Compounds: Why Salts Are Hard and Brittle
The properties of ionic compounds — high melting points, hardness, brittleness, conductivity when molten or dissolved, and solubility — each explained from the ionic lattice, with data and exceptions.
The Shape of a Water Molecule and Why It Matters
Why H₂O is bent at 104.5°, how its shape makes water polar, and how that single fact explains hydrogen bonding, high boiling point, floating ice, surface tension and water's power as a solvent.
Simple Molecular vs Giant Covalent Substances
Simple molecular vs giant covalent substances compared: structure, what breaks on melting, melting points, conductivity, solubility, hardness, examples and how to identify each type.
Single, Double and Triple Bonds Compared
Single vs double vs triple covalent bonds: shared electron pairs, sigma and pi bonds, bond length and energy data, rotation, shape, reactivity and examples from ethane to nitrogen.
Structure and Bonding Revision Guide
A one-stop structure and bonding revision checklist: ionic, covalent and metallic bonding, the four structure types, intermolecular forces, shapes, key facts, a data-identification table and exam tips.
What Is a Chemical Bond? Why Atoms Stick Together
A beginner's guide to chemical bonds: why atoms bond, the energy picture, ionic, covalent and metallic bonds, bond strength, and how bonds differ from intermolecular forces.
Why Does Ice Float? Hydrogen Bonding and Density
Why solid water is less dense than liquid water: the open hydrogen-bonded lattice of ice, the density maximum at 4 °C, what it means for lakes and life, and other substances that expand on freezing.
Why Does Water Have Such a High Boiling Point?
Water boils at 100 °C when similar molecules boil far below zero. How hydrogen bonding, water's shape and its two lone pairs explain the anomaly, and why it matters for life and climate.
How to Write Chemical Formulas from Names
A step-by-step method for writing chemical formulas from names: ionic compounds, polyatomic ions, transition metals, covalent compounds with prefixes, acids and hydrates, with worked examples.
Ionic vs. Covalent Bonds: What's the Difference?
Why sodium and chlorine give away electrons while two oxygen atoms share theirs — and how to predict which kind of bond a pair of elements will form.
The Allotropes of Carbon: Diamond, Graphite, Graphene and Fullerenes
How the same element makes the hardest natural material and one of the softest: the structures and properties of diamond, graphite, graphene, fullerenes, nanotubes and amorphous carbon.
How to Draw Lewis Dot Structures: A Step-by-Step Guide
A reliable step-by-step method for drawing Lewis structures, worked examples from water to carbon dioxide and nitrate, formal charge, resonance, and the exceptions to the octet rule.
How to Name Ionic Compounds (With Transition Metals and Polyatomic Ions)
The rules for naming ionic compounds, Roman numerals for transition metals, polyatomic ions, acids and hydrates — and how to write the formula from the name.
How to Name Covalent (Molecular) Compounds
The prefix system for naming binary covalent compounds, which element goes first, when to drop 'mono-', common exceptions like water and ammonia, and how to write formulas from names.
Common Polyatomic Ions: List, Charges and How to Remember Them
A complete list of the polyatomic ions students need, with formulas and charges, the -ate/-ite and per-/hypo- naming patterns that make them easy to remember, and how to use them in formulas.
Amorphous vs Crystalline Solids: What's the Difference?
Crystalline solids have long-range order; amorphous solids don't. Compare melting, fracture, X-ray patterns and uses, with quartz vs glass as the key example.
Average Bond Enthalpies: A Reference Table with Explanations
A grouped table of average bond enthalpies in kJ/mol, from H–H to N≡N, with the reason behind each pattern and the difference from bond dissociation energy.
How Bonding Type Predicts Melting Point
Why methane melts at −182 °C and magnesium oxide near 2,850 °C: how ionic, molecular, giant covalent and metallic bonding set melting points.
How Bonding Type Predicts Solubility
Why salt dissolves in water but not in oil, why diamond dissolves in nothing, and how to predict solubility from ionic, molecular, giant covalent or metallic bonding.
The Bonding Triangle: Ionic, Covalent and Metallic as a Continuum
How the van Arkel–Ketelaar triangle places any binary substance between ionic, covalent and metallic bonding using two electronegativity numbers.
Chemical Bonding Exam Questions with Mark-Scheme Answers
14 exam-style chemical bonding questions (41 marks) on ionic, covalent and metallic bonding, shapes, polarity and forces, with a full mark scheme.
Bonding in Benzene: Kekulé vs the Delocalised Model
Why benzene's six C–C bonds are all the same length: the Kekulé structure, its three failures, the delocalised π ring, and the ~150 kJ/mol stability it brings.
Everything About Bonding in Water
From the O–H covalent bonds and 104.5° bent shape to hydrogen bonds, open ice and the 4 °C density peak: how bonding makes water so unusual.
Graphene and Carbon Nanotubes: Structure and Bonding
How one-atom-thick graphene and rolled-up carbon nanotubes are built from sp² carbon, and how their delocalised electrons explain their strength and conductivity.
Delocalised Electrons: Where They Occur and Why They Matter
What delocalised electrons are, where to find them (benzene, carbonate, carboxylates, graphite, metals, dyes) and how they change stability, acidity, colour and conductivity.
Diamond vs Silicon Dioxide: Two Giant Covalent Structures
Diamond and silicon dioxide compared: tetrahedral networks, bond types, hardness, melting behaviour and conductivity, and how to describe each in an exam.
Formal Charge Practice Problems with Full Working
15 formal charge practice problems, from NH₄⁺ and CO to cyanate, fulminate and sulfate, with marks and an answer key that checks every charge against the ion's total.
Fullerenes: Buckyballs and Their Bonding
What C₆₀ and other fullerenes are, why every closed cage needs exactly 12 pentagons, how their bonding differs from graphite, and what they react with.
Graphite vs Graphene: One Layer Makes the Difference
Graphite and graphene compared: the same sp² carbon honeycomb, but stacked layers versus a single sheet. Structure, conductivity, strength and uses side by side.
Hybridisation Practice Problems (sp, sp², sp³) with Answers
15 exam-style hybridisation problems, from methane to allene and amides, with marks, a full answer key, sigma and pi counts, and tips for the tricky cases.