Edexcel GCSE Chemistry Paper 1 practice questions

What is on Paper 1?

• Paper 1 covers atomic structure, bonding, quantitative chemistry and chemical changes.
• It is a written paper of 1 hour 45 minutes, worth 100 marks — 50% of the GCSE.
• Questions are a mix of multiple choice, short answer, calculations and extended writing.
• Core practicals and maths skills from across the course can be examined on either paper.

Paper 1 practice questions with answers

10 original questions across the 5 Paper 1 topics. Try each one before reading the answer.

1. Atoms, elements and the periodic table

   1. An atom has 17 protons and 18 neutrons. What is its mass number?

   • • 17
   • • 18
   • • 35
   • • 1

   Answer: 35

   Mass number = protons + neutrons = 17 + 18.

2. Atoms, elements and the periodic table

   2. Why are isotopes of an element chemically identical?

   • • They have the same number of neutrons
   • • They have the same electron arrangement
   • • They have the same mass
   • • They are in different groups

   Answer: They have the same electron arrangement

   Chemistry is decided by outer electrons, which isotopes share.

3. Ionic, covalent and metallic bonding

   3. Why does sodium chloride only conduct electricity when molten or dissolved?

   • • The ions gain charge
   • • The ions become free to move
   • • New electrons are made
   • • Covalent bonds break

   Answer: The ions become free to move

   Conduction needs charged particles that can move.

4. Ionic, covalent and metallic bonding

   4. Which structure has a low melting point?

   • • Diamond
   • • Sodium chloride
   • • Carbon dioxide
   • • Copper

   Answer: Carbon dioxide

   It is a simple molecule with weak forces between molecules.

5. Moles, masses and conservation

   5. Calculate the number of moles in 88 g of CO₂ (Mr = 44).

   Answer: 2 mol

   moles = mass ÷ Mr = 88 ÷ 44.

6. Moles, masses and conservation

   6. A sealed flask reaction shows no mass change. Why?

   • • Atoms are destroyed
   • • Atoms are rearranged, not created or destroyed
   • • Gas escaped
   • • Energy has mass

   Answer: Atoms are rearranged, not created or destroyed

   Conservation of mass in a closed system.

7. Chemical changes: reactivity, acids and electrolysis

   7. Which gas is produced when an acid reacts with a metal?

   • • Oxygen
   • • Hydrogen
   • • Carbon dioxide
   • • Nitrogen

   Answer: Hydrogen

   Acid + metal produces a salt and hydrogen gas.

8. Chemical changes: reactivity, acids and electrolysis

   8. What is produced when an acid reacts with a carbonate?

   • • Hydrogen
   • • Water only
   • • Carbon dioxide, water and a salt
   • • Oxygen

   Answer: Carbon dioxide, water and a salt

   Acid + carbonate gives salt + water + carbon dioxide.

9. Energy changes: exothermic, endothermic and bond energies

   9. Which type of reaction releases energy to the surroundings?

   • • Endothermic
   • • Exothermic
   • • Neutral
   • • Catalytic

   Answer: Exothermic

   Exothermic reactions transfer energy out to the surroundings.

10. Energy changes: exothermic, endothermic and bond energies

    10. What happens to the temperature of the surroundings in an endothermic reaction?

    • • Increases
    • • Decreases
    • • Stays the same
    • • Doubles

    Answer: Decreases

    Endothermic reactions absorb energy from the surroundings, cooling them.

Where Paper 1 marks are usually lost

• Writing unbalanced symbol equations — check every element on both sides.
• Explaining properties without referring to structure, for example why ionic compounds conduct when molten.
• Skipping steps in moles and concentration calculations — method marks need visible working.
• Confusing oxidation and reduction in reactivity questions.
• Not converting units before substituting into a formula.

How to pick up the extended-answer marks

• Spend the first 30 seconds underlining the command word — 'describe', 'explain' and 'evaluate' are marked differently.
• Plan one point per mark, each carrying a scientific term and a consequence. Short linked sentences beat one long paragraph.
• For 'evaluate' questions, include a benefit, a drawback and a judgement sentence at the end.
• For required practical questions, name the control variable and how the result was measured — method detail is where the marks sit.

Timing that works under pressure

• Work at roughly one mark per minute so you keep spare time for checking at the end.
• Bank the short recall questions first, then return to the longer answers with your remaining time.
• If a question stalls for more than two minutes, write down what you know and move on — partial marks still count.
• Leave five minutes to check units, significant figures and whether any question part was skipped over a page break.

Revise each Paper 1 topic

• Atoms, elements and the periodic table (83 questions)
• Ionic, covalent and metallic bonding (83 questions)
• Moles, masses and conservation (83 questions)
• Chemical changes: reactivity, acids and electrolysis (82 questions)
• Energy changes: exothermic, endothermic and bond energies (81 questions)

Edexcel Chemistry Paper 1 FAQs

What topics are on Edexcel GCSE Chemistry Paper 1?

Paper 1 assesses atomic structure, the periodic table, bonding, quantitative chemistry and chemical changes. Required practicals and data skills linked to these topics can also be examined.

How long is Edexcel GCSE Chemistry Paper 1?

It is a 1 hour 45 minute written exam worth 100 marks, which is 50% of the GCSE. Working at about one mark per minute leaves time to check your answers.

How should I revise for Chemistry Paper 1?

Practise answering questions rather than rereading notes. Short daily sets of five questions per topic, marked straight away, expose weak areas faster than a long passive revision session.