Lesson T4.1.1

T4.1.1 Rearranging atoms in reactions Quiz: KS3 Chemistry, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson T4.1.1, Rearranging atoms in reactions: 20 multiple choice questions for the KS3 Chemistry (National Curriculum), Unit 4: Chemical reactions, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What happens to atoms in a chemical reaction?

    • They are destroyed and new atoms are created
    • They change into atoms of different elements
    • They are turned into energy and disappear
    • They are rearranged to form new substances

  2. What do the reactants become in a chemical reaction?

    • Catalysts
    • Products
    • Solvents
    • Solutes

  3. In a chemical reaction, how do the numbers of atoms of each element compare before and after?

    • They change depending on the temperature
    • There are more atoms after the reaction
    • They are the same on both sides
    • There are fewer atoms after the reaction

  4. Which substance is a reactant in the burning of methane?

    • Carbon dioxide
    • Water
    • Heat
    • Methane

  5. Why does a reaction give new substances with different properties?

    • The atoms have been destroyed and replaced
    • The atoms have lost all their mass
    • The atoms are bonded together in different arrangements
    • The atoms have changed into different elements

  6. A student writes that hydrogen atoms vanish in a reaction. What is wrong?

    • Hydrogen atoms are rearranged into a new substance, so they must still be present
    • Hydrogen atoms are heavier than all other atoms in the periodic table
    • Hydrogen atoms cannot take part in reactions because they are too light to bond
    • Hydrogen atoms only exist in liquids and so cannot appear in a gas reaction

  7. Which statement describes a reaction of iron with oxygen?

    • Iron atoms and oxygen atoms bond together to form iron oxide
    • Iron atoms turn into oxygen atoms as the metal rusts in the damp air
    • Oxygen atoms turn into iron atoms and the oxygen gas is then given off
    • Iron atoms are destroyed to release energy that heats the oxygen in the air

  8. Hydrogen and oxygen react to make water. Which best explains the change in atoms?

    • Oxygen atoms are destroyed to make new hydrogen atoms in the reaction
    • Water molecules split into new atoms that then form hydrogen and oxygen
    • Hydrogen atoms turn into oxygen atoms and the water is formed as a gas
    • Hydrogen and oxygen atoms rearrange into water molecules

  9. Which evidence shows that a chemical reaction has happened rather than a physical change?

    • The substance dissolves in water
    • The substance is cut into smaller pieces
    • A new substance with different properties forms
    • The substance changes shape in a container

  10. Why can a reaction be shown as a diagram of atoms being rearranged?

    • Because the same atoms are present before and after but in different groups
    • Because atoms only exist in the products once the reaction is finished
    • Because atoms become larger in each step of the reaction as they bond
    • Because reactions do not involve atoms, only the bonds between molecules

  11. Which change is a chemical reaction rather than a physical change?

    • Breaking a glass bottle into several sharp pieces
    • Dissolving sugar in water to make a clear solution
    • Melting ice cubes in a warm room to form liquid water
    • Burning magnesium to make magnesium oxide

  12. In a reaction, what is the name for the substances on the left-hand side of the arrow?

    • Products
    • Solutes
    • Catalysts
    • Reactants

  13. A student heats copper oxide with hydrogen and copper and water form. What happens to the atoms?

    • Hydrogen atoms turn into oxygen atoms and copper
    • Atoms in copper oxide and hydrogen are rearranged into copper and water
    • Copper atoms are created from the water formed
    • Copper oxide atoms are destroyed and replaced by hydrogen

  14. What happens to the number of atoms of each type when a reaction is balanced?

    • They are the same on both sides
    • They halve in the products
    • They are different on each side
    • They double in the products

  15. In the reaction CH4 + 2O2 -> CO2 + 2H2O, what happens to the carbon atoms?

    • One carbon atom from methane ends up in one carbon dioxide molecule
    • Carbon atoms change into oxygen atoms
    • Carbon atoms are split between the water molecules
    • Carbon atoms are destroyed and new carbon atoms are formed

  16. Why do reactions obey the idea that atoms are rearranged?

    • Atoms are destroyed when heat is applied to the reacting mixture
    • Atoms are not created or destroyed in a chemical reaction
    • Atoms can change element during a reaction when the bonds break
    • Atoms are created when energy is transferred during the reaction

  17. Which statement about reactions is NOT true?

    • Bonds in the reactants are broken and new bonds are formed in the products
    • A reaction can be shown using formulae that balance the atoms on both sides
    • Products contain the same atoms as the reactants, just arranged differently
    • The number of atoms of an element increases during a reaction

  18. Why is a word equation useful even though it does not show numbers of atoms?

    • It shows the names of reactants and products, which helps identify the reaction
    • It shows how many atoms are in each product, so the reaction can be balanced
    • It shows the speed of the reaction in seconds for each stage of the process
    • It shows the temperature at which the reaction starts and how long it lasts

  19. Sodium reacts with chlorine to make sodium chloride. What happens to the atoms?

    • Sodium atoms vanish and the salt forms from energy given off by the reaction
    • Sodium and chlorine atoms bond together in a new arrangement
    • Sodium atoms turn into chlorine atoms and the salt forms as a gas
    • Chlorine atoms split into sodium atoms that then combine into sodium chloride

  20. Which of these is the gas product when zinc reacts with hydrochloric acid and bubbles form?

    • Hydrogen
    • Oxygen
    • Carbon dioxide
    • Chlorine

All KS3 Chemistry quizzes