Science 8 · Unit 5: Materials and cycles on Earth · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. What charge does a proton have?

   • positive
   • it changes
   • negative
   • no charge
   Check

2. 2. What charge does an electron have?

   • positive
   • no charge
   • it changes
   • negative
   Check

3. 3. What charge does a neutron have?

   • positive
   • negative
   • no charge
   • double positive
   Check

4. 4. Where are protons and neutrons found?

   • in the nucleus
   • orbiting the nucleus
   • in the empty space
   • outside the atom
   Check

5. 5. Where are electrons found?

   • nowhere
   • in the nucleus
   • around the nucleus
   • inside protons
   Check

6. 6. Which particle has the smallest mass?

   • the nucleus
   • the neutron
   • the proton
   • the electron
   Check

7. 7. What is most of an atom made of?

   • neutrons
   • protons
   • solid metal
   • empty space
   Check

8. 8. What was J. J. Thomson's model of the atom?

   • a tiny nucleus with electrons around it
   • electrons scattered in a ball of positive charge (plum pudding)
   • only neutrons
   • a hollow sphere
   Check

9. 9. What did Rutherford's model add?

   • electrons inside protons
   • a tiny, dense, positive nucleus in the centre
   • a solid atom
   • no electrons
   Check

10. 10. In Rutherford's experiment, what happened to most particles fired at gold foil?

    • They stuck to the foil.
    • They melted the foil.
    • They all bounced back.
    • They went straight through.
    Check

11. 11. What did the few particles that bounced back show?

    • Atoms are completely solid.
    • Electrons are heavy.
    • Gold is magnetic.
    • There is a small, dense, positive nucleus.
    Check

12. 12. Which scientist also contributed to today's model of the atom?

    • Charles Darwin
    • Archimedes
    • James Chadwick
    • Isaac Newton
    Check

13. 13. Which statement is correct?

    • Protons have a negative charge.
    • Neutrons have an electrical charge.
    • Neutrons have more mass than electrons.
    • Electrons are in the nucleus.
    Check

14. 14. Why do scientific models of the atom change?

    • Old models were never tested.
    • New evidence from experiments shows the old model was not complete.
    • Scientists like changing things.
    • Atoms change shape every year.
    Check

15. 15. Who discovered the electron, in the late 1890s?

    • Niels Bohr
    • Ernest Rutherford
    • James Chadwick
    • J. J. Thomson
    Check

16. 16. What holds an atom together?

    • gravity between the neutrons
    • the attraction between positive protons and negative electrons
    • magnetism in the nucleus
    • glue-like neutrons around the outside
    Check

17. 17. A helium atom has 2 protons, 2 neutrons and 2 electrons. What is its overall charge?

    • zero (neutral)
    • +4
    • +2
    • −2
    Check