AQA GCSE Chemistry Chemistry Paper 1 (Higher), 2023: Question 8

10 marks · Standard Demand difficulty · Short Answer

This multi-part question tests knowledge of the periodic table, including electron configurations of noble gases, predicting chemical formulas, properties of non-metals, and the reaction of Group 2 metals with acids.

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Question

A series of five sub-questions (08.1 to 08.5) about the periodic table. 08.1 asks why argon does not form compounds. 08.2 asks for the formula of a compound between phosphorus and hydrogen. 08.3 asks if tellurium reacts with metals. 08.4 asks for two observations when barium reacts with hydrochloric acid. 08.5 asks for a balanced symbol equation for the reaction between barium and hydrochloric acid.
Question text

08 This question is about elements in the periodic table.

08.1 Argon has the atomic number 18

Explain why argon does not form compounds.

Answer in terms of electrons.

[2 marks]

08.2 Phosphorus (P) is the element below nitrogen in the periodic table.

Predict the formula of the compound formed between phosphorus and hydrogen.

[1 mark]

Formula =

08.3 Tellurium is the element with atomic number 52

Predict whether tellurium reacts with metals.

Explain your answer.

Answer in terms of the position of tellurium in the periodic table.

[2 marks]

Barium (Ba) is an element in Group 2 of the periodic table.

Barium reacts with hydrochloric acid.

08.4 Suggest two observations that could be made when barium reacts with

hydrochloric acid.

[2 marks]

08.5 Write a balanced symbol equation for the reaction between barium and

hydrochloric acid.

[3 marks]

+ → +

Mark scheme

Show the mark scheme A table showing the mark scheme for questions 08.1 through 08.5. It provides acceptable answers, extra information, and mark allocations for each part, including specific chemical formulas and observations for the reaction of barium with acid.

AO /

Question Answers Extra information Mark

Spec. Ref.

08.1 (atoms of) argon have a stable allow (atoms of) argon have a 1 AO1

arrangement of electrons full outer shell (of electrons) 4.1.2.3

4.1.2.4

4.2.1.1

(so) argon (atoms) do not share 1

/ transfer electrons

AO /

Spec. Ref.

08.2 PH3 allow H3P 1 AO2

4.1.2.1

– HEMISTRY – – 4.2.1.4

AO /

Spec. Ref.

08.3 MP2 is dependent upon MP1 AO3

being awarded 4.1.2.3

yes, because tellurium is allow yes, because tellurium is 1

towards the right of the periodic in Group 6

table

(so) tellurium is a non-metal allow (so) tellurium will gain 1

electrons (from a metal)

OR

yes, because tellurium is in the

same group as oxygen / sulfur

(1)

(and) oxygen / sulfur will react allow (so) tellurium is a non-

with metals (1) metal

allow (so) tellurium will gain

electrons (from a metal)

OR

no, because tellurium is towards

the bottom of the periodic table

(1)

(so) tellurium is a metal (1) allow (so) difficult for tellurium to

24 gain electrons (from a metal) (1)

OR

cannot predict as tellurium is

towards the bottom and to the

right of the periodic table (1)

(so) don’t know whether allow (so) don’t know whether

tellurium is a metal or non-metal tellurium will gain electrons

(1) – HEMISTRY – –

AO /

Answers Extra information Mark

Question Spec. Ref.

08.4 ignore references to floating / AO3

flames 4.1.2.1

any two from: 2 4.4.1.2

• effervescence / fizzing / ignore produces a gas 4.4.2.1

bubbles

• barium disappears allow barium gets smaller

• forms a colourless solution 25

• temperature increases

allow barium moves around

AO /

Spec. Ref.

08.5 Ba + 2 HCl → BaCl2 + H2 allow multiples 3 AO2

4.1.1.1

allow 1 mark for BaCl2 4.4.1.2

allow 1 mark for H2 4.4.2.1

ignore state symbols

– HEMISTRY – –

Total Question 8 10

Question 9

How to answer it

Periodic Table Trends and Metal Reactions

What this question tests

This question assesses your understanding of Group 0 (Noble Gas) stability, predicting chemical formulas based on group trends, identifying metal/non-metal properties by periodic position, and writing balanced symbol equations for metal-acid reactions.

Part 08.1

Argon and Chemical Bonding

Why does argon not form compounds?

💡 Key Knowledge

  • Argon is in Group 0 (the Noble Gases).
  • Atoms react to achieve a stable electron arrangement.
  • Argon's electronic structure is 2, 8, 8.

✅ Correct Answer

  • Argon atoms have a stable arrangement of electrons (or a full outer shell). [1 mark]
  • Therefore, they do not share or transfer electrons. [1 mark]

🧠 Exam Technique

The question specifically asks for an answer "in terms of electrons." If you only say "it is a noble gas" or "it is unreactive," you will not score. You must mention the full outer shell and the fact that it doesn't lose, gain, or share electrons.

Part 08.2

Predicting Chemical Formulas

Formula of Phosphorus and Hydrogen

💡 Key Knowledge

Elements in the same group react in similar ways and form compounds with similar formulas. Phosphorus is in Group 5, directly below Nitrogen.

✅ Correct Answer

Formula = PH₃ [1 mark]

(H₃P is also accepted)

🧠 Exam Technique

Think of a common compound you know involving the element above the one in the question. You likely know Ammonia is NH₃ . Since Phosphorus is in the same group as Nitrogen, it will follow the same pattern.

Part 08.3

Tellurium: Metal or Non-Metal?

Predicting reactivity based on position

🧠 Exam Technique

This is an "evaluative" question. The examiner allows several logical paths. The most common path is identifying it as a non-metal because it is on the right side of the table.

✅ Correct Answer (Option A)

  • Yes, it reacts with metals because tellurium is on the right side of the periodic table. [1 mark]
  • Therefore, tellurium is a non-metal. [1 mark]

❌ Common Errors

Students often forget that the second mark depends on the first. You must link the position (right side/Group 6) to the property (non-metal) to get both marks.

Part 08.4

Observations: Barium + Acid

What would you see?

✅ Correct Answers (Pick Two)

  • Effervescence (fizzing / bubbles).
  • The barium disappears (or gets smaller).
  • A colourless solution forms.
  • The temperature increases (exothermic).

❌ Common Errors

  • "Hydrogen is made": This is a fact, not an observation. You see bubbles, you don't "see" hydrogen.
  • "A gas is produced": Too vague. Use "fizzing" or "bubbles."
Part 08.5

The Balanced Equation

Barium + Hydrochloric Acid

📐 Step-by-Step Calculation

  1. Identify Reactants: Barium is Ba . Hydrochloric acid is HCl .
  2. Identify Products: Metal + Acid → Salt + Hydrogen. The salt is Barium Chloride. Since Barium is in Group 2, it forms Ba²⁺ ions. Chlorine forms Cl⁻ ions. The formula is BaCl₂ . Hydrogen gas is always H₂ .
  3. Balance: We have 2 Chlorines and 2 Hydrogens on the right, so we need 2 in front of the HCl .

✅ Final Equation

Ba + 2HCl → BaCl₂ + H₂

[1 mark for BaCl₂, 1 mark for H₂, 1 mark for balancing]

❌ Calculation Traps

  • Diatomic Molecules: Never write Hydrogen as just H . It must be H₂ .
  • Valency: Barium is in Group 2. A common mistake is writing BaCl instead of BaCl₂ . If your formula is wrong, your balancing will also be wrong!

Topics

Chemistry · C1: Atomic Structure and the Periodic Table · C4: Chemical Changes

Question and mark scheme from the AQA GCSE Chemistry examination, Chemistry Paper 1 (Higher), 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.