What mistakes do students make with Diamond?

Saying diamond is made of small molecules. Put it right by describing a giant covalent lattice with no separate molecules. Saying diamond conducts electricity because it contains carbon. Put it right by stating that all four outer electrons per carbon are localised in covalent bonds, so there are no delocalised electrons. Saying diamond has a high melting point because covalent bonds are weak. Put it right by stating the bonds are strong and many must be broken.

What are the exam tips for Diamond in Chemistry AQA GCSE?

Name the structure first, then link each property to a structural feature in a because clause. Use the phrase many strong covalent bonds must be broken when explaining the high melting point. State explicitly that there are no delocalised electrons or ions when explaining why diamond does not conduct electricity.

AQA · GCSE · Chemistry

Course version: 8462 · Version from Sept 2018

Students should be able to explain the properties of diamond in terms of…

Full specification wording

Diamond: Students should be able to explain the properties of diamond in terms of its structure and bonding.

Diamond is a giant covalent lattice of carbon atoms.

Checked against the AQA 8462 specification (opens in a new tab) on 21 September 2026.

Point 2 of 2

Study notes

From the checked teaching notes for this specification point.

The idea

For example: This explains its use in cutting tools and drill tips.

What earns the marks

States that each carbon atom in diamond forms four covalent bonds to four other carbon atoms.
Describes the arrangement as a giant covalent lattice or tetrahedral network with no separate molecules.
Links the high melting point to the many strong covalent bonds that must be broken.
Links the extreme hardness to the rigid three-dimensional network of strong covalent bonds.
Explains that diamond does not conduct electricity because all outer electrons are localised in covalent bonds, so there are no delocalised electrons or ions.

Common mistakes and how to put them right

Saying diamond is made of small molecules.
Put it right by describing a giant covalent lattice with no separate molecules.
Saying diamond conducts electricity because it contains carbon.
Put it right by stating that all four outer electrons per carbon are localised in covalent bonds, so there are no delocalised electrons.
Saying diamond has a high melting point because covalent bonds are weak.
Put it right by stating the bonds are strong and many must be broken.

Exam tips

Name the structure first, then link each property to a structural feature in a because clause.
Use the phrase many strong covalent bonds must be broken when explaining the high melting point.
State explicitly that there are no delocalised electrons or ions when explaining why diamond does not conduct electricity.

Try the lesson

The start of the Diamond: Students should be able to explain the properties of diamond in terms of its structure and bonding. lesson, made from checked teaching notes for this specification point.

Have a go first

Which statement describes the bonding in diamond?

Tip: press 1 to 4 to choose

Listen

Diamond is a giant covalent lattice of carbon atoms. Each carbon atom forms four single covalent bonds to four other carbon atoms, arranged tetrahedrally. Because each bond is shared between two atoms, the ratio of atoms to bonds is 1:2 and every outer electron is localised in a bond. This rigid three-dimensional network has no separate molecules and no free electrons or ions. Consequently diamond has a very high melting point because many strong covalent bonds must be broken, it is extremely hard because the lattice resists deformation, and it does not conduct electricity because there are no delocalised electrons or ions to carry charge. For example, this explains its use in cutting tools and drill tips. A strong answer earns marks for these points. States that each carbon atom in diamond forms four covalent bonds to four other carbon atoms. Describes the arrangement as a giant covalent lattice or tetrahedral network with no separate molecules. Links the high melting point to the many strong covalent bonds that must be broken. Links the extreme hardness to the rigid three-dimensional network of strong covalent bonds. A common slip: Saying diamond is made of small molecules. Instead, describing a giant covalent lattice with no separate molecules. Exam tip: Name the structure first, then link each property to a structural feature in a because clause.

See it

A top-down flowchart. At the top is a node reading 'Giant covalent lattice of carbon atoms'. From it, three branches lead down. The first branch goes to 'Each carbon atom forms four single covalent bonds to four other carbon atoms', which leads to 'Arranged tetrahedrally', which leads to 'Rigid three-dimensional network resists deformation', which leads to 'Extremely hard'. The same bonding node also leads to 'Many strong covalent bonds must be broken', which leads to 'Very high melting point'. The second branch from the top node goes directly to 'No separate molecules'. The third branch goes to 'All outer electrons localised in bonds', which leads to 'No delocalised electrons or ions', which leads to 'Does not conduct electricity'. — Shows how diamond's giant covalent lattice and its bonding lead to its high melting point, hardness and lack of electrical conductivity.

Label the diagram

Some boxes have lost their names. Pick the right name for each number.

The diagram again, with 3 boxes numbered instead of named. A top-down flowchart. At the top is a node reading 'Giant covalent lattice of carbon atoms'. From it, three branches lead down. The first branch goes to 'Each carbon atom forms four single covalent bonds to four other carbon atoms', which leads to 'Arranged tetrahedrally', which leads to 'Rigid three-dimensional network resists deformation', which leads to 'Extremely hard'. The same bonding node also leads to 'Many strong covalent bonds must be broken', which leads to 'Very high melting point'. The second branch from the top node goes directly to 'No separate molecules'. The third branch goes to 'All outer electrons localised in bonds', which leads to 'No delocalised electrons or ions', which leads to 'Does not conduct electricity'.

1Box 1
2Box 2
3Box 3

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