New
New
Year 10
Edexcel
Higher

Diamond and graphite

I can describe the properties of diamond and graphite and explain how they result from their giant covalent structures, as well as relate them to their uses.

New
New
Year 10
Edexcel
Higher

Diamond and graphite

I can describe the properties of diamond and graphite and explain how they result from their giant covalent structures, as well as relate them to their uses.

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Lesson details

Key learning points

  1. In diamond each carbon atom is bonded to four others with strong covalent bonds to form a giant covalent structure.
  2. Diamond is very hard, has a very high melting point and does not conduct electricity (makes it good for cutting tools).
  3. In graphite, each carbon atom is covalently bonded to three others to form layers of hexagonal rings.
  4. There are only weak forces between the layers in graphite which can easily be rubbed apart (makes it a good lubricant).
  5. Graphite conducts electricity because it has delocalised electrons which can move and carry charge/current.

Common misconception

Students may think all carbon forms are alike, ignoring structure's impact on properties.

Emphasise structure-property relationships. Use models to show how diamond's and graphite's differing bonds affect their characteristics.

Keywords

  • Allotrope - A different structural form of an element, e.g. graphite and diamond are allotropes of carbon.

  • Giant covalent - A large regular arrangement of atoms all joined together by covalent bonds.

  • Forces of attraction - Forces of attraction refer to any force that causes two or more substances to come together.

  • Delocalised - Particles are said to be delocalised when they are free to move through a structure (delocalised electrons can carry an electrical current).

Use interactive 3D models to demonstrate lattice structures. Compare physical samples of graphite and diamond (crystal/glass are useful substitutes - just don't test the hardness!) to highlight differences.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
The presence of which type of bond is a key feature in giant covalent structures?
Ionic bonds
Correct answer: Covalent bonds
Metallic bonds
Q2.
Which property is typical of substances with giant covalent structures?
Correct answer: high melting and boiling points
conductivity in their solid state
low melting and boiling points
soluble in water
Q3.
What distinguishes a giant covalent structure from a simple molecular structure?
the type of atoms involved
the presence of ionic bonds
Correct answer: the size and regularity of the structure
their electrical conductivity
their solubility in water
Q4.
Which diagram below shows a model of a giant covalent substance?
sodium chloride (NaCl)
Correct answer: silicon dioxide (SiO₂)
nitrogen (N₂)
iron (Fe)
Q5.
Which properties are typically found in simple molecular substances but not in giant ionic structures?
high electrical conductivity
Correct answer: inability to dissolve in water
Correct answer: low melting and boiling points
flexibility and malleability
Q6.
In giant covalent structures, atoms are bonded covalently in a large 3D lattice resulting in high melting and boiling points. Match each part of this sentence to the correct term.
Correct Answer:bonding,covalent

covalent

Correct Answer:structure type,giant covalent

giant covalent

Correct Answer:property,high melting and boiling points

high melting and boiling points

Correct Answer:structure description,large 3D lattice

large 3D lattice

6 Questions

Q1.
What is an allotrope?
a type of chemical bond
Correct answer: a different structural form of an element
a kind of molecular geometry
a category of organic compounds
Q2.
What makes diamond so hard?
intermolecular forces
delocalised electrons
hexagonal rings
Correct answer: covalent bonds
Q3.
Why can graphite be used as a lubricant?
strong covalent bonds within atoms
Correct answer: weak intermolecular forces between layers
delocalised electrons
high melting point
ability to conduct electricity
Q4.
In diamond, each carbon atom forms covalent bonds.
Correct Answer: 4, four
Q5.
True or false? In graphite, each carbon atom is bonded to four other carbon atoms.
True
Correct answer: False
Q6.
Graphite conducts electricity because it has which can move and carry charge/current.
Correct Answer: delocalised electrons