Lesson 8.1.1

8.1.1 Nucleon and proton number and alpha particle scattering Quiz: Pearson Edexcel Physics, Unit 8

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 8.1.1, Nucleon and proton number and alpha particle scattering: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 8: Nuclear and Particle Physics, written with Revision Ninja.

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The 20 questions

  1. What is the nucleon number (mass number) of a nucleus?

    • The number of electrons in a neutral atom
    • The number of protons in the nucleus only
    • The total number of protons and neutrons in the nucleus
    • The number of neutrons in the nucleus only

  2. What is the proton number (atomic number) of an element?

    • The number of electrons in the outermost shell of the atom
    • The number of neutrons in each nucleus of that element
    • The number of protons in each nucleus of that element
    • The total number of nucleons in each nucleus of that element

  3. How many neutrons are in a nucleus of uranium-235, written as the nuclide ^235_92 U?

    • 327
    • 143
    • 92
    • 235

  4. In Rutherford's alpha particle scattering experiment, what did most alpha particles do when passing through a thin gold foil?

    • They were absorbed by the gold foil and never emerged
    • They bounced straight back towards the source in every case
    • They were all deflected through exactly 90 degrees
    • They passed through with little or no deflection

  5. What did the observation of a small number of alpha particles scattered through large angles show about the atom?

    • The atom is a uniform sphere of positive charge with electrons embedded in it
    • The atom consists of a dense mixture of electrons and neutrons only
    • The atom has a small, dense, positively charged nucleus
    • The atom has no electrons and is composed solely of neutral particles

  6. How many neutrons are in an atom of iron-56, written as ^56_26 Fe?

    • 30
    • 56
    • 82
    • 26

  7. How many neutrons are in an atom of carbon-14, written as ^14_6 C?

    • 14
    • 6
    • 20
    • 8

  8. An isotope of chlorine has 17 protons and 20 neutrons. What is its nucleon number?

    • 20
    • 3
    • 17
    • 37

  9. A neutral atom of lithium-7 has nucleon number 7 and proton number 3. How many electrons does it have?

    • 10
    • 7
    • 3
    • 4

  10. Why do some alpha particles in the Rutherford experiment deflect through large angles?

    • They are attracted by the neutral neutrons in the gold foil at large distances
    • They come very close to the nucleus, where the electrostatic repulsion from its concentrated positive charge is strong
    • They collide head-on with electrons, which are heavier than the alpha particles
    • They lose kinetic energy in the foil and are therefore deflected by gravity

  11. Why were large-angle deflections in alpha scattering observed so rarely?

    • Most alpha particles were absorbed by the electrons in the gold foil
    • The nucleus is very small compared with the atom, so only a few alpha particles pass close enough to it
    • The alpha particles were moving too slowly to be deflected by the nucleus
    • The electrons in the atom shield the nucleus completely from alpha particles

  12. What is the nucleon number of an alpha particle, which is a helium nucleus, written as ^4_2 He?

    • 2
    • 4
    • 8
    • 6

  13. The radius of an atom is approximately 10^-10 m and the radius of its nucleus is approximately 10^-15 m. Roughly how many times larger is the atom than its nucleus?

    • a quadrillion times, or 10^15
    • 100000 times, or 10^5
    • 1000 times, or 10^3
    • 10 billion times, or 10^10

  14. An atom has proton number 6 and nucleon number 13. How many neutrons does it have?

    • 6
    • 7
    • 19
    • 13

  15. Which change would increase the number of alpha particles scattered through large angles in the experiment?

    • Using a target nucleus with a greater proton number, so the positive charge of each nucleus is larger
    • Using an uncharged target with the same nucleon number and no protons
    • Using a thinner foil with fewer atoms along the alpha particle path
    • Using alpha particles with a smaller mass and kinetic energy

  16. Which statement is true of the nuclides ^12_6 C and ^14_6 C?

    • They have the same proton number but different nucleon numbers, so they are isotopes
    • They have the same nucleon number but different proton numbers, so they are isotopes
    • They have the same number of neutrons but different numbers of protons
    • They have different proton and nucleon numbers, so they are different elements with no link

  17. How many neutrons does a nucleus of uranium-238, written as ^238_92 U, contain?

    • 92
    • 330
    • 146
    • 238

  18. A nucleus with nucleon number 210 and proton number 84 emits an alpha particle. What are the nucleon number and proton number of the new nucleus?

    • A = 206 and Z = 86
    • A = 208 and Z = 84
    • A = 206 and Z = 82
    • A = 206 and Z = 84

  19. Why did Rutherford conclude that the nucleus of an atom must carry positive charge?

    • Neutral alpha particles were attracted towards each nucleus in the foil
    • The gold foil was observed to glow when struck by alpha particles
    • Electrons were observed to be deflected towards the centre of the gold foil
    • Positively charged alpha particles were strongly deflected through large angles, which requires repulsion from a positive charge

  20. A student claims alpha scattering showed that electrons are located inside the nucleus. Which response is correct?

    • The student is wrong: the scattering established a small, dense, positive nucleus of protons and neutrons, with electrons outside it
    • The student is right, because the electrons were the particles deflected by the alpha particles
    • The student is right, because the nucleus was shown to contain only electrons and no protons
    • The student is wrong, because alpha scattering showed the nucleus has no charge at all

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