Edexcel A-Level Chemistry Paper 2, June 2017: Question 2
3 marks · Easy difficulty · Multiple Choice
Identify the common structural feature, bond angles, and differences in properties among diamond, graphene, and graphite.
Practise this questionQuestion
Question text
2 Diamond, graphene and graphite are different forms of carbon.
(a) The structural feature that graphene and graphite have in common is that the
carbon atoms are arranged in
(1)
A layers with each atom bonded to four others
B hexagonal and pentagonal rings within a layer
C hexagonal rings within a layer
D a three-dimensional structure
(b) The bond angles within a layer of graphene and a layer of graphite are
(1)
A 90° and 109.5°
B all 109.5°
C 109.5° and 120°
D all 120°
(c) One way in which diamond differs from graphene and graphite is that only diamond has
(1)
A a high melting temperature
B a precise molecular formula
C poor electrical conductivity
D a giant structure
(Total for Question 2 = 3 marks)
Mark scheme
Show the mark scheme
Question
Answer Mark
Number
2(a) The only correct answer is C (hexagonal rings within a layer) (1)
A is not correct because in the layers of graphite and graphene the carbon atoms are bonded to
three other carbon atoms and not four
B is not correct because graphite and graphene do not have pentagonal rings within their layers
D is not correct because graphene is a two-dimensional structure consisting of a single layer
Question
Answer Mark
Number
2(b) The only correct answer is D (all 120°) (1)
A is not correct because the angles within a layer of graphite and graphene are neither 90° nor
109.5° but are all 120°
B is not correct because the angles within a layer of graphite and graphene are not 109.5° but are
all 120°
C is not correct because there are no angles within a layer of graphite and graphene that are 109.5° but
they are all 120°
Question
Answer Mark
Number
2(c) The only correct answer is C (poor electrical conductivity) (1)
A is not correct because both graphene and graphite are similar to diamond in having a high
melting temperature
B is not correct because neither graphene nor graphite nor diamond have a precise molecular formula
since they are giant molecular structures
C is not correct because graphene, graphite and diamond are all giant molecular structures
(Total for Question 2 = 3 marks)
How to answer it
Structure and Bonding in Carbon Allotropes
What this question tests
This multiple-choice question assesses your understanding of giant covalent structures, specifically comparing the bonding, arrangement, bond angles, and electrical conductivity of diamond, graphite, and graphene.
Structural Features of Graphene and Graphite
✅ Correct Answer: C
Hexagonal rings within a layer. Both graphite and graphene consist of sheets where each carbon atom is bonded to 3 others in a flat, repeating 6-membered ring network.
💡 Key Knowledge
- In graphite/graphene, carbon uses 3 of its 4 outer electrons for covalent bonding.
- The 4th electron is delocalized across the structure.
- Layers are held together by weak intermolecular forces (London forces).
❌ Common Errors
- Choosing A (bonded to 4 others) confuses graphite with diamond.
- Choosing D misses the fact that graphene is strictly a 2D single-layer structure.
Bond Angles in Graphene and Graphite
✅ Correct Answer: D
All 120 degrees. Because each carbon atom in a layer has 3 bonding pairs and 0 lone pairs, Electron Pair Repulsion Theory (VSEPR) dictates a trigonal planar geometry with 120 degrees bond angles.
🧠 Exam Technique
Whenever you see questions asking for bond angles in carbon allotropes, quickly sketch or recall the coordination number: coordination number 3 = trigonal planar (120 degrees); coordination number 4 = tetrahedral (109.5 degrees).
❌ Common Errors
- Selecting B or C (109.5 degrees) applies the tetrahedral angle of diamond to layer structures.
Differences Between Diamond and Layered Allotropes
✅ Correct Answer: C
Poor electrical conductivity. Diamond has all 4 outer electrons tied up in single covalent bonds, leaving no free or delocalized charge carriers. In contrast, graphite and graphene conduct electricity due to delocalized electrons parallel to the layers.
💡 Key Knowledge
All three (diamond, graphite, graphene) are giant covalent structures with very high melting temperatures and do not have precise molecular formulas (unlike simple molecules like CO₂ ).
❌ Common Errors
- Choosing A is a mistake because all of these giant covalent lattices possess high melting temperatures due to the requirement to break strong covalent bonds.
Topics
Physical Chemistry · Topic 2: Bonding and Structure
Question and mark scheme from the Edexcel A-Level Chemistry examination, Paper 2, June 2017. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.