Atomic Structure | AQA GCSE Combined Science Trilogy Physics, Foundation tier (8464)

Atomic Structure

138 questions
8 subtopics
Physics Paper 1
Physics Paper 1

Atomic Structure is examined in Physics Paper 1.

It covers the structure of an atom, mass number, atomic number and isotopes, from the plum pudding model to the nuclear model, Chadwick, the neutron, and comparing the models, radioactive decay and nuclear radiation, nuclear equations, half-lives and the random nature of radioactive decay and radioactive contamination.

Sample questions from Atomic Structure

Answer each one closed book first, then open the answer.

The structure of an atom

Where in an atom are the electrons found?

Show the answer
Surrounding the nucleus, outside it.
Mass number, atomic number and isotopes

How is the number of neutrons in an atom worked out?

Show the answer
Subtract the atomic number from the mass number.
From the plum pudding model to the nuclear model

Which discovery led scientists to propose the plum pudding model?

Show the answer
The discovery of the electron.
Chadwick, the neutron, and comparing the models

Compare the charge and the mass of a neutron with those of a proton.

Show the answer
A neutron carries no charge while a proton is positively charged, but the two particles have almost the same mass.
Radioactive decay and nuclear radiation

Name the four kinds of nuclear radiation that may be emitted from a nucleus.

Show the answer
Alpha particles, beta particles, gamma rays and neutrons.
Nuclear equations

What happens to the mass number of a nucleus when it emits an alpha particle?

Show the answer
It decreases by 4.
Half-lives and the random nature of radioactive decay

Does the half-life of an isotope change as more and more of the sample decays?

Show the answer
No, the half-life stays the same however much of the sample has already decayed.
Radioactive contamination

State the key difference between contamination and irradiation.

Show the answer
In contamination the radioactive atoms are on or in the object itself, while in irradiation the object is only exposed to radiation coming from a separate source.

The 8 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
The structure of an atom	The radius of an atom and why atoms cannot be seen with a light microscope, the nucleus of protons and neutrons and its charge, electrons and their charge, the size of the nucleus and where the mass is concentrated, why an atom is mostly empty space, and how electrons sit in energy levels and move when an atom absorbs or emits electromagnetic radiation.	17
Mass number, atomic number and isotopes	Why an atom has equal numbers of electrons and protons and no overall charge, atomic number and mass number, working out the number of neutrons, reading the two numbers written before a chemical symbol, isotopes and how they differ, and how an atom becomes a positive ion by losing an outer electron.	17
From the plum pudding model to the nuclear model	Why scientific models change, atoms as indivisible before the discovery of the electron, the plum pudding model, the alpha particle scattering experiment and its conclusions, why the plum pudding model could not explain the results, Bohr's electrons orbiting at specific distances, and the later discovery of protons in the nucleus.	17
Chadwick, the neutron, and comparing the models	Chadwick's evidence for the neutron, where it sits and why it was hard to detect, what the scattering results forced, and how the plum pudding and nuclear models differ.	14
Radioactive decay and nuclear radiation	How unstable nuclei decay, activity and its unit, count-rate and the detectors that measure it, the four kinds of nuclear radiation, what alpha particles, beta particles and gamma rays are, how strongly each ionises, what absorbs each and their ranges in air, and why smoke detectors use an alpha emitter.	18
Nuclear equations	What a nuclear equation represents, the two totals that balance, the numbers given to alpha and beta particles, and how each kind of emission changes mass number and atomic number.	18
Half-lives and the random nature of radioactive decay	The random nature of radioactive decay, half-life in terms of nuclei and of count-rate, why activity falls over time, finding a half-life from data and from a graph of count-rate against time, and why the background count is subtracted before a half-life is worked out.	18
Radioactive contamination	Radioactive contamination and where its hazard comes from, why the type of radiation matters and alpha emitters inside the body, irradiation and how it differs from contamination, comparing the hazards of sealed and loose sources, precautions such as lead-lined containers and protective clothing, and why findings on radiation effects are shared and peer reviewed.	19

Atomic Structure is 138 of the 994 questions in the guide.Get the guide, £7

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.