AQA GCSE Combined Science: Trilogy Chemistry Paper 1 (Foundation), June 2025: Question 2
12 marks · Low Demand difficulty · Short Answer
Answer questions on the properties, bonding, structures, and formula masses of elements in the same row of the periodic table, including lithium, carbon, nitrogen, fluorine, and neon.
Practise this questionQuestion
Question text
02 Lithium, carbon, nitrogen, fluorine and neon are elements in the same row of the
periodic table.
02.1 What is the chemical symbol of lithium?
Use the periodic table.
[1 mark]
02.2 Lithium has metallic bonding.
Which electrons are involved in metallic bonding?
[1 mark]
Tick ( ) one box.
Delocalised electrons from the inner shell
Delocalised electrons from the outer shell
Fixed electrons in the inner shell
Fixed electrons in the outer shell 8
02.3 Lithium reacts with fluorine to produce lithium fluoride.
Draw one line from each substance to the particle diagram that represents
the substance.
[3 marks]
02.4 Table 2 shows the electrical conductivity of three substances.
Table 2
Electrical conductivity Electrical conductivity
Substance
when solid when liquid
C Poor Poor
D Poor Good
E Good Good
Lithium fluoride is an ionic compound.
Which substance is lithium fluoride?
[1 mark]
Tick ( ) one box.
C D 10 E
02.5 Carbon can exist in different forms.
Figure 4 represents one form of carbon.
Figure 4
What is the name of the form of carbon in Figure 4?
[1 mark]
Tick ( ) one box.
Buckminsterfullerene
*09*Diamond
Graphite
02.6 Carbon and fluorine form a compound with the formula CF4
Calculate the relative formula mass (Mr) of CF4
Relative atomic masses (Ar): C = 12 F = 19
[2 marks]
Relative formula mass (11M ) =
r
02.7 Figure 5 represents a molecule of nitrogen.
*10* Figure 5
What is the total number of shared electrons in the covalent bond
shown in Figure 5?
[1 mark]
02.8 Lithium and nitrogen form a compound with the formula Li3N
Complete the sentence.
Choose the answer from the box.
[1 mark]
nitrate nitride nitrogen
The name of the compound with the formula Li3N is lithium .
02.9 Neon does not react with other elements to form compounds.
Why is neon unreactive?
[1 mark]
Tick ( ) one box.
Neon has a stable arrangement of electrons.
Neon is a gas at room temperature.
Neon is a non-metallic element.
Mark scheme
Show the mark scheme
Question 2
AO /
Question Answers Extra information Mark
Spec. Ref.
02.1 Li 1 AO1
5.1.1.1
AO /
Spec. Ref.
02.2 delocalised electrons from the 1 AO1
outer shell 5.2.1.5
AO /
Question Answers Mark
Spec. Ref.
02.3 AO3
5.1.1.1
5.2.2.1
do not accept more than one line from a box on the left
AO /
Spec. Ref.
02.4 D 1 AO3
5.2.2.3
AO /
Spec. Ref. 9
02.5 diamond 1 AO1
5.2.3.1
AO /
Spec. Ref.
02.6 (relative formula mass =) 1 AO2
12 + (19 × 4) 5.3.1.2
= 88 1
AO /
Spec. Ref.
02.7 6 allow 3 pairs 1 AO2
5.2.1.1
5.2.1.4
AO /
Spec. Ref.
02.8 nitride 1 AO2
5.1.1.1
AO /
Spec. Ref.
02.9 neon has a stable arrangement 1 AO1
of electrons 5.1.2.4
Total Question 2 12
How to answer it
Period 2 Elements: Bonding, Structure & Formulae
- Periodic Table fundamentals: Chemical symbols and group trends (noble gases).
- Types of bonding & structure: Metallic lattices, giant ionic lattices, simple diatomic covalent molecules, and giant covalent networks (diamond).
- Properties of ionic compounds: Electrical conductivity in solid vs molten/liquid states.
- Quantitative Chemistry: Step-by-step relative formula mass (Mᵣ) calculation.
- Dot-and-cross diagrams: Interpreting covalent bonding and counting shared electrons.
- Chemical nomenclature: Naming binary non-metal/metal compounds (-ide vs -ate).
Chemical Symbol of Lithium
Periodic Table Recall [1 Mark]
✅ Correct Answer
Li
❌ Common Errors
- Writing LI (capital 'I') — chemical symbols always have only the first letter capitalised.
- Writing the full word "Lithium" instead of the chemical symbol.
Electrons in Metallic Bonding
Metallic Structure & Bonding [1 Mark]
✅ Correct Answer
Tick: Delocalised electrons from the outer shell
💡 Key Knowledge
Metals consist of a giant lattice of positive metal ions surrounded by a "sea" of delocalised electrons that are free to move throughout the structure. These come exclusively from the atoms' outer shell.
Matching Substances to Particle Diagrams
Visualising States and Lattices [3 Marks]
✅ Correct Pairings
- Lithium solid → 2nd diagram (regular lattice of tightly packed identical spheres).
- Fluorine gas → 1st diagram (widely spaced pairs of identical bonded atoms, representing F₂ diatomic molecules).
- Lithium fluoride solid → 4th diagram (regular alternating grid of two different coloured spheres, representing Li⁺ and F⁻ ions).
🧠 Exam Technique
Use elimination: Fluorine is a gas, so particles must be spaced far apart. Lithium fluoride is a compound, so its diagram must show two different particle types arranged regularly in a solid lattice.
❌ Common Errors
Drawing more than one line from any box on the left automatically forfeits the mark for that substance.
Identifying Lithium Fluoride from Conductivity Data
Properties of Ionic Compounds [1 Mark]
✅ Correct Answer
Tick: D
💡 Key Knowledge
- Solid ionic compound: Ions are held tightly in fixed positions in the lattice, so it is a poor conductor.
- Liquid (molten) ionic compound: The lattice breaks down; ions are free to move and carry charge, so it is a good conductor.
❌ Common Misconception
Choosing E: Metals conduct in both solid and liquid states (due to delocalised electrons). Lithium fluoride is ionic, not metallic!
Allotropes of Carbon
Giant Covalent Structures [1 Mark]
✅ Correct Answer
Tick: Diamond
💡 Key Knowledge
- Diamond: Rigid 3D tetrahedral network; each carbon atom forms 4 covalent bonds.
- Graphite: Hexagonal layers with weak intermolecular forces between layers.
- Buckminsterfullerene: Spherical hollow cage (C₆₀).
Calculating Relative Formula Mass (Mᵣ) of CF₄
Quantitative Chemistry [2 Marks]
📐 Step-by-Step Calculation
Given: Aᵣ of C = 12, Aᵣ of F = 19
- Identify the number of each atom: 1 × Carbon, 4 × Fluorine
- Multiply by respective Aᵣ values:
C: 1 × 12 = 12
F: 4 × 19 = 76 - Add them together:
Mᵣ = 12 + 76 = 88
❌ Common Errors
- Forgetting to multiply Fluorine by 4: doing 12 + 19 = 31 (scores 0).
- Multiplying the whole mass: 12 × 19 × 4 (scores 0).
Shared Electrons in Nitrogen (N₂) Molecule
Covalent Dot-and-Cross Diagrams [1 Mark]
✅ Correct Answer
6 (or 3 pairs)
🧠 Exam Technique
Read the question carefully: It asks for the total number of shared electrons, not the number of covalent bonds. Each covalent bond is 1 pair of electrons.
Count every dot and cross inside the overlap area: 3 crosses + 3 dots = 6 electrons.
❌ Common Errors
Writing "3" because it has a triple bond. 3 bonds contain 6 electrons in total.
Naming the Compound Li₃N
Chemical Nomenclature [1 Mark]
✅ Correct Answer
Lithium nitride
💡 Key Knowledge
- Compounds with only two elements (a metal and a non-metal) end in -ide (e.g. oxide, sulfide, nitride).
- The ending -ate means oxygen is also present (e.g. lithium nitrate = LiNO₃).
Why Neon is Unreactive
Group 0 / Noble Gases Electronic Structure [1 Mark]
✅ Correct Answer
Tick: Neon has a stable arrangement of electrons.
💡 Key Knowledge
Neon is in Group 0 (Noble Gases). Its outer shell is full (8 electrons: 2,8). Because its electron arrangement is already completely stable, it does not need to gain, lose, or share electrons to form bonds.
❌ Common Trap
While neon is a gas and a non-metal, those are properties, not the chemical explanation for why it does not react.
Topics
Chemistry · C1: Atomic Structure and the Periodic Table · C2: Bonding, Structure and the Properties of Matter · C3: Quantitative Chemistry
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Chemistry Paper 1 (Foundation), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.