Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Covalent Bonding — exam questions
12 original Incandio exam-style questions on Covalent Bonding, 26 marks, about 26 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Covalent Bonding — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
7 command words run through this set, and on Pearson Edexcel International GCSE Chemistry each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- State what is meant by (1–2 marks)
- the definition
- Give (1–2 marks)
- a short factual answer — the most common chemistry command
- Describe (2–5 marks)
- developed, linked statements of what happens or what is observed Misread as: giving one bare observation where the tariff asked for a developed account
- Explain (2–4 marks)
- the reason, in terms of particles, bonding, energy or equilibrium Misread as: describing the observation without giving the chemistry that causes it
- Suggest (1–3 marks)
- a plausible answer applying taught chemistry to an unfamiliar substance
- Complete (1–4 marks)
- the missing entries in a table, equation or diagram
Assessed on Paper 1 (4CH1/1C) and Paper 2 (4CH1/2C), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Chemistry (4CH1) — statements 1.44 · 1.46 · 1.45. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 12 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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Table 1 — four small covalent molecules Molecule Formula Shared pairs of electrons hydrogen H₂ 1 hydrogen chloride HCl 1 water H₂O to be found methane CH₄ 4 (a)
(1)Complete
Complete Table 1 by giving the number of shared pairs of electrons in a molecule of water.
Table 1 — four small covalent molecules Molecule Formula Shared pairs of electrons hydrogen H₂ 1 hydrogen chloride HCl 1 water H₂O to be found methane CH₄ 4 (b)
(2)Describe
Describe how the outer electrons are arranged in a molecule of hydrogen chloride, HCl.
Table 1 — four small covalent molecules Molecule Formula Shared pairs of electrons hydrogen H₂ 1 hydrogen chloride HCl 1 water H₂O to be found methane CH₄ 4 (c)
(3)Explain
Explain, using Table 1, why methane contains four shared pairs while hydrogen contains only one.
Table 1 — four small covalent molecules Molecule Formula Shared pairs of electrons hydrogen H₂ 1 hydrogen chloride HCl 1 water H₂O to be found methane CH₄ 4 (d)
(3)Suggest
Ammonia, NH₃, is not in Table 1. Suggest how many shared pairs it contains, and explain how you decided.
Table 1 — four small covalent molecules Molecule Formula Shared pairs of electrons hydrogen H₂ 1 hydrogen chloride HCl 1 water H₂O to be found methane CH₄ 4 (Total for Question 1 = 9 marks)
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(1)Which
Which is present in a single covalent bond?
Description A one shared pair of electrons B one electron transferred from one atom to the other C two shared pairs of electrons D a sea of delocalised electrons (Total for Question 2 = 1 mark)
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(1)State what is meant by
State what is meant by a covalent bond.
(Total for Question 3 = 1 mark)
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(1)Give
Give the number of covalent bonds formed by one carbon atom in a molecule of methane.
(Total for Question 4 = 1 mark)
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(2)Describe
Describe, in terms of their outer electrons, what happens when two chlorine atoms join to form a molecule of Cl₂.
(Total for Question 5 = 2 marks)
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(3)Explain
Explain why a shared pair of electrons holds two atoms together.
(Total for Question 6 = 3 marks)
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(2)Give
Give the number of shared pairs of electrons in a molecule of nitrogen, N₂, and in a molecule of carbon dioxide, CO₂.
(Total for Question 7 = 2 marks)
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(3)Suggest
Two atoms are pushed closer together than their normal bond length. Suggest why the energy of the pair rises rather than falling further.
(Total for Question 8 = 3 marks)
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(4)Explain
Explain why a molecule of oxygen contains a double bond while a molecule of chlorine contains a single one.
(Total for Question 9 = 4 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 12 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain Covalent Bonding to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against August Kekulé over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Covalent Bonding — What two atoms do when neither can afford to give an electron away.
- All of Incandio Chemistry · Incandio Exam Practice