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Chemical Bonding: an interactive chemistry course

Published 8 Nov 20265 min read

Chemical Bonding is an interactive chemical bonding course about why atoms join together and how the way they join explains what substances are like. Its 23 short sections cover why atoms bond, ionic bonding and formulae, giant lattices, covalent bonds including double and triple bonds, bond energies, molecules and giant structures, metallic bonding, electronegativity, molecular shapes, polarity and intermolecular forces.

It opens with two hydrogen atoms sliding into an energy well, settling at a bond 74 picometres long, so you can see that a bond forms because the bonded atoms have less energy than the separate ones.

What the course covers

Sections	Topic	What you do
1 to 3	Why atoms bond, and three ways to a full shell	Name the bond type for each substance
4 to 7	Ionic bonding, ion charges, formulae and lattices	Balance the charges to find an ionic formula
8 to 11	Covalent bonding, double and triple bonds, bond energies	Count bonding and lone pairs, then add up bond energies
12 to 13	Simple molecules and giant structures	Sort substances into giant ionic, simple molecular and giant covalent
14 to 15	Metallic bonding	Match each property to the bonding that explains it
16 to 17	Electronegativity	Order bonds from least to most polar
18 to 21	Shapes of molecules and polarity	Predict a shape, then sort molecules into polar and non-polar
22 to 23	Forces between molecules	Read a chart of hydride boiling points

Three kinds of bond

Metals and non-metals form ionic bonds: the metal gives electrons to the non-metal and the oppositely charged ions attract in a giant lattice. Non-metals form covalent bonds by sharing pairs of electrons. In metallic bonding, metal atoms release their outer electrons into a sea of delocalised electrons around a lattice of positive ions. Our ionic bonding and covalent bonding guides cover each in detail.

Structure explains properties

The bonding decides the structure, and the structure decides the properties. Giant ionic lattices have high melting points and conduct when molten or dissolved. Simple molecules have strong bonds inside them but weak forces between them, so they melt and boil at low temperatures. Delocalised electrons let metals conduct and bend without breaking.

Shapes and polarity

Electron pairs around a central atom repel and spread as far apart as they can, which sets the shape of a molecule. Electronegativity, how strongly an atom pulls on shared electrons, makes some bonds polar, and the shape decides whether those pulls cancel out. Water is bent, so its polar bonds do not cancel and the molecule is polar.

Two lone pairs on oxygen push the bonds closer together, so water is bent at about 104.5°

Try a question from the course

Look at what the substance is made of. Sodium chloride joins a metal to a non-metal: ionic. Carbon dioxide is two non-metals, so it is covalent. Copper is a metal on its own, so it has metallic bonding.

Now name the bond type for a few more substances, then press Mark to check your answers in the course.

Press Mark to have your answer marked in the Chemical Bonding course.

Who this course is for

GCSE chemistry and combined science students revising ionic, covalent and metallic bonding and structures.
A-level and other advanced students working on electronegativity, shapes, polarity and intermolecular forces.
Anyone who wants to know why salt dissolves, why diamond is hard and why metals conduct.

What you need to know first

The course page suggests Atomic Structure first: you need electron shells, outer electrons and ions. The bond energy practice uses simple addition.

How long it takes

There are 23 sections and most take a few minutes. Learners without a plan can open two sections of a course a day, in order, so the whole course takes 12 days. A plan removes the daily limit and lets you go straight to any topic, such as molecular shapes.

Guided courseOrganic ChemistryPut covalent bonding to work: alkanes, alkenes, functional groups, isomers and polymers.

Common questions

Is this chemical bonding course free?

You can take every section without paying, two sections a day, in order. A plan removes the daily limit and opens any section straight away.

What are the three types of chemical bonding?

Ionic bonding between metals and non-metals, where electrons are transferred; covalent bonding between non-metals, where electrons are shared; and metallic bonding in metals, where outer electrons are delocalised.

How do you work out an ionic formula?

Find each ion's charge from its group, then take just enough of each ion for the charges to cancel. Magnesium forms Mg²⁺ and chlorine forms Cl⁻, so magnesium chloride is MgCl₂.

What is electronegativity?

How strongly an atom attracts the shared electrons in a covalent bond. Fluorine is the most electronegative element. A big difference between two atoms makes a polar bond.

Why do simple molecular substances have low boiling points?

Boiling only has to overcome the weak forces between molecules, not the strong covalent bonds inside them.

What decides the shape of a molecule?

The number of electron pairs, bonding and lone, around the central atom. They repel each other and spread as far apart as possible. Lone pairs repel slightly more, squeezing bond angles.

Revision cards

Say the answer first, then flip the card to check it.

Where to go next

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Molar Mass Calculator
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Chemical Bonding
Ionic, covalent and metallic bonds, and why atoms stick together
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GCSE Chemistry Higher
A new exam-style paper every day, with instant marking and a mark scheme
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