Atomic StructureAQA GCSE Physics: Topic test

20 questions, 54 marks

AQA GCSE Physics

Atomic Structure topic test

Total 54 marks

Name

Class

Date

1
A sodium atom has 11 protons, 12 neutrons and 11 electrons.
(a)
What is the overall electrical charge of the sodium atom?
[1 mark]
APositive, because there are more protons than electrons
BNegative, because there are more neutrons than protons
CZero, because the number of electrons equals the number of protons
DPositive, because neutrons carry a small positive charge
(b)
What are the atomic number and mass number of this sodium atom?
[1 mark]
AAtomic number 11, mass number 23
BAtomic number 23, mass number 11
CAtomic number 12, mass number 11
DAtomic number 11, mass number 12
(c)
This sodium atom loses one outer electron to become an ion. State the overall charge of the resulting ion and explain why it has this charge.
[2 marks]
Total for question 1: 4 marks
2
A science historian is tracing how scientists' model of the atom changed over time, from an early model in which the atom was a sphere of positive charge with negative electrons embedded within it, up to a scattering experiment that led to a very different model.
(a)
What was the earlier model described in the passage, in which the atom is a sphere of positive charge with electrons embedded in it, called?
[1 mark]
AThe nuclear model
BThe Bohr model
CThe plum pudding model
DThe current model
(b)
What result from the alpha particle scattering experiment could not be explained by the earlier model, leading to a change in the model?
[1 mark]
AAll alpha particles passed straight through the foil with no deflection at all
BA small number of alpha particles were deflected by large angles, and a few bounced almost straight back
CThe alpha particles were absorbed completely and none passed through or were deflected
DThe alpha particles turned into beta particles as they passed through the foil
(c)
Explain why the result described above led scientists to replace the earlier model with the nuclear model of the atom.
[2 marks]
Total for question 2: 4 marks
3
A cobalt-60 nucleus (atomic number 27, mass number 60) is unstable and undergoes beta decay, emitting a high-speed electron from the nucleus.
(a)
Explain what happens inside the nucleus during this beta decay, and state what happens to the atomic number and mass number of the nucleus as a result.
[3 marks]
(b)
Write a balanced nuclear equation for the beta decay of cobalt-60 into nickel (Ni), showing the atomic and mass numbers of both the cobalt nucleus and the resulting nickel nucleus, and the beta particle emitted.
[4 marks]
Total for question 3: 7 marks
4
A hospital stores a supply of iodine-131, a beta- and gamma-emitting isotope used to treat thyroid conditions, which has a half-life of 8 days. A fresh batch arrives with an activity of 320 MBq, and is stored for 24 days before some of it is used.
(a)
Calculate the activity of the iodine-131 sample after being stored for 24 days, showing how you used the half-life to work this out.
[6 marks]
(b)
Explain why iodine-131's relatively short half-life makes it particularly suitable for this medical use, and evaluate the precautions hospital staff must take when handling and storing it, given that it emits both beta and gamma radiation.
[6 marks]
Total for question 4: 12 marks
5
A domestic smoke detector contains a small sealed source of americium-241, which decays by emitting alpha particles, ionising the air between two electrodes inside the detector so that a tiny current normally flows.
(a)
Which statement correctly describes an alpha particle?
[1 mark]
AA high-speed electron ejected from the nucleus
BElectromagnetic radiation emitted from the nucleus
CA neutral particle with no mass
DTwo protons and two neutrons, the same as a helium nucleus
(b)
Why is an alpha-emitting source suitable for use sealed inside a smoke detector, given the properties of alpha radiation?
[1 mark]
AAlpha radiation has a very long range in air and passes easily through walls, so it can be detected from far away
BAlpha radiation cannot ionise air at all, so it is completely safe
CAlpha radiation has no mass and passes straight through smoke particles without interacting
DAlpha radiation is strongly ionising over a very short range in air, so it can ionise the air between the electrodes but does not travel far enough to be a significant hazard while sealed inside the detector
(c)
Explain how the smoke detector uses the ionising effect of the alpha radiation to detect smoke.
[2 marks]
Total for question 5: 4 marks
6
An airline pilot who flies long-haul routes at high altitude for many years is found, over the course of a year, to receive a higher radiation dose from cosmic rays than a colleague who works entirely in the airline's ground office.
(a)
Which of these is a natural source of background radiation, of the kind received by the pilot?
[1 mark]
AFallout from past nuclear weapons testing
BCosmic rays from space
CRadioactive waste from a nuclear power station
DMedical X-ray equipment
(b)
Why does the pilot receive a higher dose of cosmic ray radiation than the ground-based office worker?
[1 mark]
AThe pilot spends more time at high altitude, where there is less atmosphere above to absorb cosmic rays before they are received
BThe pilot's aircraft generates its own radioactive emissions
CGround-based workers are always shielded by lead in office buildings
DCosmic rays only exist above a certain altitude and do not reach the ground at all
(c)
Explain why radiation dose depends on a person's occupation and location, using the pilot and the office worker as examples.
[2 marks]
Total for question 6: 4 marks
7
Inside a nuclear power station reactor core, a slow-moving neutron is absorbed by a uranium-235 nucleus, which becomes unstable and splits into two smaller daughter nuclei, releasing three fast neutrons and energy.
(a)
Describe what happens when the uranium-235 nucleus undergoes this fission process, including what is released.
[3 marks]
(b)
Explain how the neutrons released by this fission event can lead to a chain reaction, and how this chain reaction is controlled inside the reactor core so that it does not proceed uncontrollably as it would in a nuclear weapon.
[4 marks]
Total for question 7: 7 marks
8
Deep inside the core of a star, extreme temperature and pressure force light nuclei, such as hydrogen, to join together to form heavier nuclei, releasing energy. Elements up to and including iron can be formed this way, and much heavier elements, including some radioactive isotopes later used in medicine, are produced in a supernova explosion at the end of a massive star's life.
(a)
Describe the process of nuclear fusion occurring inside the star's core, and explain why extremely high temperature and pressure are needed for it to happen.
[6 marks]
(b)
Some of the radioactive isotopes produced in a supernova, like those used in medicine today, are hazardous but also useful. Evaluate the balance of risks and benefits of using radioactive isotopes in medicine, using an example use in your answer.
[6 marks]
Total for question 8: 12 marks

End of questions