Lesson T6.1.5

T6.1.5 Atoms and molecules Quiz: KS3 Physics, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson T6.1.5, Atoms and molecules: 20 multiple choice questions for the KS3 Physics (National Curriculum), Unit 6: Matter and particles, 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 is an atom?

    • A particle of light released from a flame when it is heated
    • The smallest part of an element that keeps its chemical identity
    • The part of a substance that can be split up by heating it
    • A group of molecules joined together by a magnetic attraction

  2. What is an element?

    • A substance made of two or more types of atom joined together
    • A mixture of substances that can be separated by filtering
    • A substance that changes state at room temperature
    • A substance made of only one type of atom

  3. What is a molecule?

    • A particle of pure carbon only
    • Two or more atoms bonded together
    • A mixture of two different liquids
    • A single atom with a charge

  4. How many atoms are there in one molecule of water?

    • Three
    • Four
    • One
    • Two

  5. Which of these is a compound?

    • Air, a mixture of gases that are not chemically joined together
    • Water, made from hydrogen and oxygen atoms chemically joined
    • Gold, made of only gold atoms packed closely together in metal
    • Pure oxygen gas, made of O2 molecules of one element only

  6. What is the best description of an atom in Dalton's model?

    • A tiny solid sphere that cannot be divided
    • A large hollow ball filled with fluid
    • A tiny cloud of charge with no mass
    • A small sphere that changes size with temperature

  7. What does the particle model say about the atoms in a solid?

    • They are close together in a regular arrangement
    • They are charged and repel one another across the small gaps
    • They are far apart and moving freely through the empty space
    • They are destroyed when they are heated up to high temperature

  8. Which word describes a substance made of molecules that each contain only one type of atom?

    • Element
    • Mixture
    • Solution
    • Compound

  9. What is the approximate size of an atom?

    • About one ten-millionth of a millimetre
    • About one metre across
    • About the size of a football
    • About the size of a grain of sand

  10. Why can a sugar solution be separated into sugar and water?

    • Sugar and water are physically mixed, not chemically joined
    • Sugar is a compound made from gold atoms that are chemically joined
    • Water contains no atoms at all, so it cannot be bonded with sugar
    • Sugar and water are made from the same atoms in a mixture

  11. In a mixture of hydrogen and oxygen gases, what is true?

    • The gases have already formed water molecules in the container
    • The gases have no atoms in them, so they cannot be mixed up
    • The gases are not chemically bonded to each other
    • The mixture contains only one element, which is a pure gas

  12. Which particle model feature explains why a gas can mix with another gas?

    • Particles of both gases move randomly and spread through each other
    • Particles of both gases are destroyed when the gases are mixed up
    • Particles of both gases stay fixed in place inside the container
    • Particles of both gases are magnetic and attract each other strongly

  13. Which of these is an element?

    • Carbon dioxide, a compound of carbon and oxygen
    • Salt, a compound of sodium and chlorine
    • Water, a compound of hydrogen and oxygen
    • Carbon, containing only carbon atoms

  14. Why are atoms of the same element identical to each other?

    • They have the same number of protons
    • They have the same mass in every case
    • They are the same colour in every substance
    • They are all charged in the same way

  15. What is the best way to describe a molecule of oxygen gas?

    • A group of hydrogen atoms
    • Two oxygen atoms that are not bonded
    • Two oxygen atoms bonded together
    • One oxygen atom with a charge

  16. Which statement about compounds is correct?

    • Compounds contain only one type of atom
    • Compounds have properties different from the elements they contain
    • Compounds are always mixtures
    • Compounds always have the same properties as their elements

  17. Which of these shows atoms of two different elements chemically joined?

    • A molecule of oxygen gas
    • A piece of pure iron
    • A carbon dioxide molecule
    • A bubble of nitrogen gas

  18. Why do we use models of atoms and molecules?

    • They replace the need for experiments
    • They prove that atoms are visible through a microscope
    • They help us explain observations that cannot be seen directly
    • They show that atoms never move

  19. In the particle model, what is the basic building block of all matter?

    • Protons alone, packed inside the nucleus
    • Magnetic fields that surround the magnets
    • Electrons alone, moving around the nucleus
    • Atoms and molecules

  20. Which of these statements about atoms is correct?

    • Atoms are made entirely of magnetic particles that attract each other
    • Atoms can be seen clearly with the naked eye in good light
    • Atoms are the same size as molecules of water in every case
    • Atoms are far too small to see with an ordinary light microscope

All KS3 Physics quizzes