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GCSE Physics · Topic Test
Atomic Structure
FREE Online Physics GCSE Course35minutes
41marks
13questions
How it works
- Answer each question. Type into the boxes or pick an option, and use paper for working and drawings.
- Press Check my answers at the end of the question. Tick-box and number answers are marked for you.
- For written answers, compare yours with the mark scheme and tick each point you made. We highlight the key words we spot, but you decide, just like an examiner.
You will need: paper, a pen, a pencil, a ruler and a calculator. Your answers save automatically in this browser.
1
Question 1
1 marksAtoms contain three types of particle.
The particles in the nucleus of the atom are:
(1 mark)
Mark scheme
Answer: C neutrons and protons.
2
Question 2
1 marksWhich column correctly shows the charges of the atomic particles relative to a proton?
| Particle | A Relative charge | B Relative charge | C Relative charge |
|---|---|---|---|
| Electron | −1 | +1 | −1 |
| Neutron | 0 | 0 | −1 |
| Proton | +1 | −1 | +1 |
(1 mark)
Mark scheme
Answer: A
3
Question 3
1 marksScientists have been able to make new elements in nuclear reactors. One of these new elements is fermium. An atom of fermium is represented by the symbol below.
Fermium
How many protons does this atom contain?
(1 mark)
Mark scheme
Answer: B 100
4
Question 4
1 marksA radioactive source emits alpha particles.
What might this source be used for?
(1 mark)
Mark scheme
Answer: B to make a smoke detector work
5
Question 5
6 marks(a)
Uranium atoms do not always have the same number of neutrons.
What are atoms of the same element that have different numbers of neutrons called?
(1 mark)
Mark scheme
Answer: isotopes
💡 Ions have a different number of electrons. Atoms with different numbers of neutrons are isotopes.
(b)
By emitting an alpha particle, an atom of uranium-235 decays into an atom of thorium. An alpha particle is the same as a helium nucleus.
Complete the equation by writing the correct number in each of the two boxes.
Alpha decay of uranium-235
(2 marks)
Mark scheme
Top box: 231
💡 In alpha decay the mass number goes down by 4.
💡 90 is the atomic number: it goes in the bottom box.
Bottom box: 90 (correct order only)
💡 In alpha decay the atomic number goes down by 2.
💡 231 is the mass number: it goes in the top box.
(c)(i)
The diagram shows an atom of uranium-235 being split into several pieces.
Uranium-235 splitting
Name the process shown in the diagram.
(1 mark)
Mark scheme
Process: (nuclear) fission (accept “fision”; not any spelling that could be confused with fusion)
💡 Fusion is two small nuclei joining. Here one large nucleus splits.
(c)(ii)
Name the particles labelled X.
(1 mark)
Mark scheme
Particles X: neutron / neutrons
💡 X starts the reaction by hitting the nucleus, and three more are released. They have no charge.
(d)
Uranium-235 is used as a fuel in some nuclear reactors. Name another substance used as a fuel in some nuclear reactors.
(1 mark)
Mark scheme
Fuel: plutonium (-239) (accept Pu; accept MOX, mixed oxide; not uranium-238 or hydrogen)
💡 The question asks for another substance, and uranium-238 isn’t accepted.
💡 Hydrogen is the fuel for fusion (in stars), not for fission reactors.
6
Question 6
1 marksWhich column correctly shows the size of a nucleus relative to an atom?
| A Relative radius | B Relative radius | C Relative radius | |
|---|---|---|---|
| Nucleus | 0 | 1/2000 | 1/10 000 |
| Atom | 1 | 1 | 1 |
(1 mark)
Mark scheme
Answer: C
7
Question 7
1 marksWhen a bound electron moves from a higher energy level to a lower energy level, what does it emit?
(1 mark)
Mark scheme
Answer: electromagnetic radiation (general words, such as “light”, are not accepted)
💡 The mark scheme wants electromagnetic radiation. Visible light is one kind, but “light” on its own is too general here.
💡 “Energy” is too general: it carries the energy away as electromagnetic radiation.
8
Question 8
4 marks(a)
A neutral atom has no overall charge. Explain this in terms of its particles.
(2 marks)
Mark scheme
Tick each marking point your answer makes:
(b)
Complete the sentence.
An atom that loses an electron is called an ________ and has an overall ________ charge.
(2 marks)
Mark scheme
called an: ion
💡 Isotopes differ in their number of neutrons. An atom that has lost or gained electrons is an ion.
overall charge: positive
💡 Losing a negative electron leaves more protons than electrons, so the charge is positive.
9
Question 9
7 marks(a)
There are many isotopes of the element molybdenum (Mo). What do the nuclei of different molybdenum isotopes have in common?
(1 mark)
Mark scheme
Tick each marking point your answer makes:
⚠️ This mark scheme says “same atomic number” on its own is not enough. Say “the same number of protons”.
(b)
When the nucleus of a molybdenum-99 atom decays, it emits radiation and changes into a nucleus of technetium-99.
Decay of molybdenum-99
What type of radiation is emitted by molybdenum-99?
(1 mark)
Mark scheme
Radiation: beta
💡 Alpha decay would lower the mass number by 4. Here it stays at 99.
💡 Gamma doesn’t change the atomic number, but it goes from 42 (Mo) to 43 (Tc).
Give a reason for your answer.
(1 mark)
Mark scheme
Any one of these scores (max 1):
(c)
Technetium-99 has a short half-life and emits gamma radiation. What is meant by the term ‘half-life’?
(1 mark)
Mark scheme
Tick each marking point your answer makes:
(d)(i)
Technetium-99 is used by doctors as a medical tracer. In hospitals it is produced inside a technetium generator by the decay of molybdenum-99 nuclei.
The graph shows how the number of nuclei in a sample of molybdenum-99 changes with time as the nuclei decay.
Decay of molybdenum-99
A technetium generator will continue to produce enough technetium-99 until 80% of the original molybdenum nuclei have decayed.
After how many days will the molybdenum-99 inside a technetium-99 generator need replacing? Show clearly your calculation and how you use the graph to get your answer.
days
(2 marks)
Mark scheme
Number of days: 6.2 days (accept 6.2 – 6.3)
💡 80 000 is the number left when only 20% have decayed. When 80% have decayed, 20 000 are left.
💡 That’s the half-life (50 000 left). Keep going down to 20 000 left.
Final answer not right? You can still earn method marks. Tick each step you wrote down (max 1):
(d)(ii)
Even though there may be a risk, doctors frequently use radioactive substances for medical diagnosis and treatments. Suggest why.
(1 mark)
Mark scheme
Tick each marking point your answer makes:
10
Question 10
4 marksIn this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
Some substances are radioactive. They may emit alpha or beta particles.
Describe the characteristics of alpha particles and beta particles in terms of their:
- structure
- penetration through air and other materials.
(4 marks)
Mark scheme
Alpha particles: tick each point you made
Beta particles: tick each point you made
| 0 | No relevant content. | 0 |
|---|---|---|
| Level 1 | A basic description of at least one of the particles in terms of its characteristics. | 1 |
| Level 2 | A clear description of the characteristics of both particles, or a full description of either alpha or beta particles. | 2–3 |
| Level 3 | A clear and detailed description of both alpha and beta particles in terms of their characteristics. | 4 |
Your mark:
Show a model answer
An alpha particle is a helium nucleus: two protons and two neutrons. Alpha particles are very poorly penetrating. They travel only a few centimetres in air and are stopped by a thin sheet of paper or by the outer layer of skin.
A beta particle is a fast-moving electron that comes from the nucleus when a neutron turns into a proton. Beta particles are more penetrating than alpha particles: they can travel several metres in air and pass through paper and thin metal foil, but are stopped by a few millimetres of aluminium.
11
Question 11
6 marksThe ‘plum pudding’ model of the atom was used by scientists in the early part of the 20th century to explain atomic structure.
The ‘plum pudding’ model
(a)
Those scientists knew that atoms contained electrons and that the electrons had a negative charge. They also knew that an atom was electrically neutral overall.
What did this allow the scientists to deduce about the ‘pudding’ part of the atom?
(1 mark)
Mark scheme
Tick each marking point your answer makes:
(b)
An experiment, designed to investigate the ‘plum pudding’ model, involved firing alpha particles at a thin gold foil.
The experiment
If the ‘plum pudding’ model was correct, then most of the alpha particles would go straight through the gold foil. A few would be deflected, but by less than 4°.
The results of the experiment were unexpected. Although most of the alpha particles did go straight through the gold foil, about 1 in every 8 000 was deflected by more than 90°.
Why did this experiment lead to a new model of the atom, called the nuclear model, replacing the ‘plum pudding’ model?
(1 mark)
Mark scheme
Tick each marking point your answer makes:
(c)(i)
The diagram shows the paths, A, B and C, of three alpha particles. The total number of alpha particles deflected through each angle is also given.
Paths of three alpha particles
Using the nuclear model of the atom, explain the three paths, A, B and C.
Path A
(1 mark)
Mark scheme
Tick each marking point your answer makes:
Path B
(1 mark)
Mark scheme
Tick each marking point your answer makes:
Path C
(1 mark)
Mark scheme
Any one of these scores (max 1):
(c)(ii)
Using the nuclear model, the scientist E. Rutherford devised an equation to predict the proportion of alpha particles that would be deflected through various angles. The results of the experiment were the same as the predictions made by Rutherford.
What was the importance of the experimental results and the predictions being the same?
(1 mark)
Mark scheme
Tick each marking point your answer makes:
12
Question 12
4 marksWhen an atom of bismuth-212 emits an alpha particle, the atom decays into an atom of thallium. An alpha particle is the same as a helium nucleus.
(i)
The equation below represents the alpha decay of bismuth-212. Complete the equation by writing the correct number in each of the two boxes.
Alpha decay of bismuth-212
(2 marks)
Mark scheme
Top box: 208
💡 In alpha decay the mass number goes down by 4.
💡 81 is the atomic number: it goes in the bottom box.
Bottom box: 81 (correct order only)
💡 In alpha decay the atomic number goes down by 2.
💡 208 is the mass number: it goes in the top box.
(ii)
It is impossible for the alpha decay of bismuth-212 to produce the same element as the beta decay of bismuth-212. Explain why.
(2 marks)
Mark scheme
Tick each marking point your answer makes:
⚠️ The mass number doesn’t decide which element it is, so it earns no marks here. The number of protons does.
13
Question 13
4 marksThe picture shows a man at work in a factory that uses radioactive materials.
The radioactive material is kept behind glass shields. The man wears gloves so that he cannot touch the radioactive material directly.
Working with radioactive materials
To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.
Explain, as fully as you can, why these precautions are taken.
(4 marks)
Mark scheme
Up to 3 marks for the physics, plus 1 for quality of writing. Tick each point your answer makes (max 4):
or 1 mark each for any of these (content max 3):
Your results
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| Question | Q1 | Q2 | Q3 | Q4 | Q5 | Q6 | Q7 | Q8 | Q9 | Q10 | Q11 | Q12 | Q13 | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Out of | 1 | 1 | 1 | 1 | 6 | 1 | 1 | 4 | 7 | 4 | 6 | 4 | 4 | 41 |
| Your mark | – | – | – | – | – | – | – | – | – | – | – | – | – | 0 |
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