Particles and Nuclear Structure

What Particles and Nuclear Structure covers

Particles and Nuclear Structure is examined in Component 3, Light, Nuclei and Options, Section A, which every student sits. It covers the Rutherford alpha particle scattering experiment, coulomb repulsion in the plum pudding and Rutherford models, quarks and leptons: the first generation, antiparticles, annihilation and their symbols, hadrons: baryons, antibaryons and mesons, quark composition of the proton, neutron and pions, the four fundamental interactions and conservation laws in particle reactions.

The 8 subtopics

Each one has its own page.

• The Rutherford alpha particle scattering experimentArrangement used in the alpha particle scattering experiment and three main observations of the alpha scattering experiment.Open →
• Coulomb repulsion in the plum pudding and Rutherford modelsRecall questions on what each model predicted for alpha scattering, what was actually observed and what each observation implied, why a large-angle deflection rules out a diffuse positive charge, and estimating the nuclear size from the distance of closest approach.Open →
• Quarks and leptons: the first generationTwo first-generation leptons and give their symbols, two first-generation quarks and give their symbols and charge of an up quark in coulombs.Open →
• Antiparticles, annihilation and their symbolsAntiparticle of the electron called, charge of the anti-up quark and of the anti-down quark and antiparticle of the electron neutrino.Open →
• Hadrons: baryons, antibaryons and mesonsRecall questions on what a hadron is and which force acts on it, the division into baryons and mesons and the quark content of each, baryon number and its values, why the proton is the only stable baryon, and why every meson is unstable.Open →
• Quark composition of the proton, neutron and pionsRecall questions on the charges of the first-generation quarks, the compositions of the proton and the neutron and the charge arithmetic that confirms them, the compositions of the charged pions, antiparticle compositions, and why no quark is ever found alone.Open →
• The four fundamental interactionsRecall questions on naming the four forces and their exchange particles, which particles feel each, their relative strengths and ranges, which force is responsible for beta decay and why only it can change quark flavour, and why gravity dominates on the astronomical scale.Open →
• Conservation laws in particle reactionsRecall questions on conserving charge, baryon number and lepton number, the values assigned to each class of particle, applying all three to a proposed reaction to test whether it can occur, and why energy availability is a separate question from the conservation rules.Open →

What you need to know

Answer each one before you reveal it.

Take Particles and Nuclear Structure further

The same content, four other ways.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Describe the arrangement used in the alpha particle scattering experiment.

   Model answer

   A beam of α particles from a radioactive source was fired at a very thin gold foil inside an evacuated chamber. A zinc sulfide screen and microscope that could be swung round the foil counted the scintillations arriving at each angle.

2. 2

   Why did the scattering chamber have to be evacuated?

   Model answer

   α particles are strongly ionising and are absorbed within a few centimetres of air. Removing the air let them reach the foil and the detector with their energy intact.

3. 3

   Why was the gold foil made extremely thin?

   Model answer

   A thin foil makes it very likely that an α particle meets only one layer of atoms. Each deflection can then be read as a single scattering event rather than the sum of many small ones.

4. 4

   State the three main observations of the alpha scattering experiment.

   Model answer

   The great majority of α particles went straight through with no measurable deflection, a small fraction were deflected through large angles, and about one in 8000 was turned back through more than 90°.

5. 5

   What does the fact that most α particles passed straight through tell us about an atom?

   Model answer

   It tells us that the atom is mostly empty space. The volume actually occupied by anything able to deflect an α particle is a tiny fraction of the volume of the atom.

6. 6

   What does a deflection through a large angle tell us about the positive charge in an atom?

   Model answer

   It tells us the positive charge is concentrated into a very small volume rather than spread through the atom. Only a large charge packed close together can repel an α particle strongly enough to turn it round.

What is inside Levo

Six ways to work the same material.

Particles and Nuclear Structure revision questions

What does Particles and Nuclear Structure cover in Eduqas A-Level Physics?

8 subtopics: the rutherford alpha particle scattering experiment, coulomb repulsion in the plum pudding and rutherford models, quarks and leptons: the first generation, antiparticles, annihilation and their symbols, hadrons: baryons, antibaryons and mesons, quark composition of the proton, neutron and pions, the four fundamental interactions and conservation laws in particle reactions. Each one has its own page with questions and model answers.

How is Particles and Nuclear Structure organised?

By the Eduqas A420QS specification, subtopic by subtopic, so it matches the order you are taught it in.