Name: Date:
P4 - Test 3 ATOMIC STRUCTURE
GCSE Mark Grade AQA PHYSICS
Materials For this paper you must have: Ruler Pencil and Rubber Scientific calculator, which you are expected to use when appropriate Instructions Answer all questions Answer questions in the space provided All working must be shown
Information The marks for the questions are shown in brackets
www.examqa.com (a) Nuclear power stations generate about 14% of the world’s electricity. 1 (i) Uranium-235 is used as a fuel in some nuclear reactors.
Name one other substance used as a fuel in some nuclear reactors.
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(ii) Energy is released from nuclear fuels by the process of nuclear fission.
This energy is used to generate electricity.
Describe how this energy is used to generate electricity.
Do not explain the nuclear fission process.
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(b) The diagram shows the nuclear fission process for an atom of uranium-235.
Complete the diagram to show how the fission process starts a chain reaction.
(2)
Page 1 of 40 www.examqa.com (c) The diagram shows the cross-section through a nuclear reactor.
The control rods, made from boron, are used to control the chain reaction. Boron atoms absorb neutrons without undergoing nuclear fission.
Why does lowering the control rods reduce the amount of energy released each second from the nuclear fuel?
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Page 2 of 40 www.examqa.com In 2011 an earthquake caused severe damage to a nuclear power station in Japan. 2
The damage led to the release of large amounts of radioactive iodine-131 into the atmosphere.
(a) The table gives some information about an atom of iodine-131 .
Complete the table.
mass number 131
number of protons 53
number of neutrons (1)
(b) Complete the sentence.
The number of protons in an atom is called the proton number or
the ...... number. (1)
(c) An atom of iodine-131 decays into an atom of xenon (Xe) by emitting a beta particle.
(i) The decay of iodine-131 can be represented by the equation below.
Complete the equation by writing the correct number in each of the two boxes.
(2)
(ii) A sample of rainwater contaminated with iodine-131 gives a count rate of 1200 counts per second.
Calculate how many days it will take for the count rate from the sample of rainwater to fall to 75 counts per second.
Half-life of iodine-131 = 8 days
Show clearly how you work out your answer.
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Page 3 of 40 www.examqa.com (iii) If people drink water contaminated with iodine-131, the iodine-131 builds up in the thyroid gland. This continues until the thyroid is saturated with iodine-131 and cannot absorb any more. The radiation emitted from the iodine-131 could cause cancer of the thyroid.
In Japan, people likely to be drinking water contaminated with iodine-131 were advised to take tablets containing a non-radioactive isotope of iodine.
Suggest why this advice was given.
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(a) Sources of background radiation are either natural or man-made. 3 Which two of the sources listed in the box are natural sources of background radiation?
Draw a ring around each of your answers.
cosmic rays nuclear accidents X-rays radon gas (2)
Page 4 of 40 www.examqa.com (b) A teacher used a Geiger-Műller (GM) tube and counter to measure the background radiation in her laboratory. The teacher reset the counter to zero, waited one minute and then took the count reading. The teacher repeated this two more times.
The three readings taken by the teacher are given in the table.
Count
17
21
19
(i) The three readings are different.
What is the most likely reason for this?
Tick ( ) one box.
The teacher did not reset the counter to zero.
Radioactive decay is a random process.
The temperature in the laboratory changed.
(1)
(ii) Calculate the mean (average) value of the three readings given in the table.
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Mean (average) value = ...... counts (1)
Page 5 of 40 www.examqa.com (iii) The diagram shows how the teacher used the GM tube and counter to measure the radiation emitted from a radioactive source.
The counter was reset to zero. The count after one minute was 159.
Calculate how many counts were due to the radiation from the radioactive source.
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Counts due to the radiation from the radioactive source = ...... (1)
Page 6 of 40 www.examqa.com (iv) The teacher then put a powerful magnet between the radioactive source and the GM tube.
The counter was reset to zero. The number on the counter shows the count after one minute.
What type of radiation was being emitted from the radioactive source?
Draw a ring around your answer.
alpha beta gamma
Explain the reason for your answer.
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(c) At the end of the lesson the teacher put the radioactive source back inside its storage box.
Why is the inside of the box lined with lead?
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Page 7 of 40 www.examqa.com (d) Which one of the following questions cannot be answered by scientific study?
Tick ( ) one box.
Where does background radiation come from?
What is meant by the half-life of a radioactive source?
Should radioactive waste be dumped in the oceans?
(1) (Total 10 marks)
The diagram shows the structure of an atom. 4
Not drawn to scale
(a) In 1931 scientists thought that atoms contained only protons and electrons.
Suggest what happened in 1932 to change the idea that atoms contained only protons and electrons.
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Page 8 of 40 www.examqa.com (b) The table gives information about the particles in an atom.
Complete the table by adding the names of the particles.
Particle Relative Mass Relative Charge
1 0
very small –1
1 +1 (2) (Total 3 marks)
Stars go through a life cycle. About 90 % of all stars are in the ‘main sequence’ period of the life 5 cycle.
(a) Stars are stable during the ‘main sequence’ period of the life cycle.
Why?
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(b) The table gives an estimated time for the number of years that three stars, X, Y and Z, will be in the ‘main sequence’ period of their life cycle.
Relative mass of the star Estimated ‘main sequence’ Star compared to the Sun period in millions of years
X 0.1 4 000 000
Y 1.0 9 000
Z 40.0 200
(i) This data suggests that there is a pattern linking the mass of a star and the number of years the star is in the ‘main sequence’ period of its life cycle.
What is the pattern suggested by the data?
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Page 9 of 40 www.examqa.com (ii) Scientists cannot give the exact number of years a star will be in the ‘main sequence’ period.
Suggest why.
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(iii) Nuclear fusion is the process by which energy is released in stars.
Which one of the following can be concluded from the data in the table?
Draw a ring around the correct answer in the box to complete the sentence.
faster than
The rate of nuclear fusion in a large star is the same as in a small star.
slower than
Explain the reason for your answer.
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Page 10 of 40 www.examqa.com (c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
Describe what happens to a star much bigger than the Sun, once the star reaches the end of the ‘main sequence’ period of its life cycle.
Your answer should include the names of the stages the star passes through.
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(a) A teacher used a Geiger-Műller (GM) tube and counter to measure the background 6 radiation in her laboratory.
The teacher reset the counter to zero, waited one minute and then took the count reading. The teacher repeated the procedure two more times.
(i) Background radiation can be either from natural sources or from man-made sources.
Name one man-made source of background radiation.
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Page 11 of 40 www.examqa.com (ii) The three readings taken by the teacher are given in the table.
Count after
one minute
15
24
18
The readings given in the table are correct.
Why are the readings different?
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(b) Some scientists say they have found evidence to show that people living in areas of high natural background radiation are less likely to develop cancer than people living in similar areas with lower background radiation.
The evidence these scientists found does not definitely mean that the level of background radiation determines whether a person will develop cancer.
Suggest a reason why.
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(c) An atom of the isotope radon-222 emits an alpha particle and decays into an atom of polonium.
An alpha particle is the same as a helium nucleus. The symbol below represents an alpha particle.
(i) How many protons and how many neutrons are there in an alpha particle?
Number of protons = ......
Number of neutrons = ...... (2)
Page 12 of 40 www.examqa.com (ii) The decay of radon-222 can be represented by the equation below.
Complete the equation by writing the correct number in each of the two boxes.
(2)
(d) The graph shows how, in a sample of air, the number of radon-222 nuclei changes with time.
Time in days
Use the graph to find the half-life of radon-222.
Show clearly on the graph how you obtain your answer.
Half-life = ...... days (2) (Total 9 marks)
Page 13 of 40 www.examqa.com A doctor uses the radioactive isotope technetium-99 to find out if a patient’s kidneys are working 7 correctly.
The doctor injects a small amount of technetium-99 into the patient’s bloodstream. Technetium-99 emits gamma radiation.
If the patient’s kidneys are working correctly, the technetium-99 will pass from the bloodstream into the kidneys and then into the patient’s urine.
Detectors are used to measure the radiation emitted from the kidneys.
The level of radiation emitted from each kidney is recorded on a graph.
(a) How do the graphs show that technetium-99 is passing from the bloodstream into each kidney?
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Page 14 of 40 www.examqa.com (b) By looking at the graphs, the doctor is able to tell if there is a problem with the patient’s kidneys.
Which one of the following statements is correct?
Put a tick ( ) in the box next to your answer.
Only the right kidney is working correctly.
Only the left kidney is working correctly.
Both kidneys are working correctly.
Explain the reason for your answer.
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There are many different isotopes of gold. The isotope, gold-198, is radioactive. 8 An atom of gold-198 decays by emitting a beta particle.
(a) Complete the following sentences.
All atoms of gold have the same number of ......
and the same number of ......
The atoms from different isotopes of gold have different numbers of ......
A beta particle is an ...... emitted
from the ...... of an atom. (3)
Page 15 of 40 www.examqa.com (b) The graph shows how the count rate from a sample of gold-198 changes with time.
Time in days
Use the graph to calculate the half-life of gold-198.
Show clearly on the graph how you obtain your answer.
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Half-life = ...... days (2)
Page 16 of 40 www.examqa.com (c) The diagram shows a map of a river and the river estuary.
Environmental scientists have found that water flowing into one part of the river estuary is polluted. To find where the pollution is coming from, the scientists use a radioactive isotope, gold-198.
The gold-198 is used to find where the pollution is coming from.
Explain how.
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Page 17 of 40 www.examqa.com The diagram represents an atom of beryllium. The three types of particle that make up the atom 9 have been labelled.
(a) Use the labels from the diagram to complete the following statements.
Each label should be used once.
The particle with a positive charge is ......
The particle with the smallest mass is ......
The particle with no charge is ...... (2)
(b) What is the mass number of a beryllium atom?
Draw a ring around your answer.
4 5 9 13
Give a reason for your answer.
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Page 18 of 40 www.examqa.com The pie chart shows the average proportions of background radiation from various sources in the 10 UK.
(a) Three sources of background radiation are given in List A. Statements about sources of background radiation are given in List B.
Draw one line to link each source of background radiation in List A to the statement about that source given in List B.
Draw only three lines.
List A List B
Are used to show broken bones.
X-rays
The radiation comes from outer
space.
Cosmic rays
Comes from soil containing a
radioactive isotope of potassium.
Radon gas
On average gives 50% of all
background radiation.
(3)
Page 19 of 40 www.examqa.com (b) The level of background radiation from cosmic rays is not the same everywhere. For every 30 metres above sea level, the amount of background radiation increases by one unit.
The diagram shows the position of two villages, A and B, built on a hill.
How is the amount of background radiation from cosmic rays different in village A compared to village B?
To obtain full marks, you must include a calculation in your answer.
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Page 20 of 40 www.examqa.com The pie chart shows the sources of the background radiation and the radiation doses that the 11 average person in the UK is exposed to in one year. Radiation dose is measured in millisieverts (mSv).
(a) (i) What is the total radiation dose that the average person in the UK receives?
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Total radiation dose = ...... mSv (1)
(ii) A student looked at the pie chart and then wrote down three statements.
Which one of the following statements is a correct conclusion from this data?
Put a tick ( ) in the box next to your answer.
In the future, more people will be exposed to a
greater proportion of radon gas.
People that have never had an X-ray get
50 % of their radiation dose from radon gas.
The radiation dose from natural sources
is much greater than from artificial sources.
(1)
Page 21 of 40 www.examqa.com (b) The concentration of radon gas inside a home can vary from day to day.
The table gives data for the radiation measured in homes in four different parts of the UK. The radiation was measured using two detectors, one in the living room and one in the bedroom. The measurements were taken over 3 months.
Number of Number of Average Maximum Area of the UK homes in the homes in the radiation radiation area sample in Bq/m3 in Bq/m3
A 590 000 160 15 81
B 484 000 130 18 92
C 221 000 68 000 162 10 000
D 318 000 35 300 95 6 900
(i) Give one reason why the measurements were taken over 3 months using detectors in different rooms.
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(ii) Use information from the table to suggest why a much higher proportion of homes were sampled in areas C and D than in areas A and B.
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Page 22 of 40 www.examqa.com In the early part of the 20th century, scientists used the ‘plum pudding’ model to explain the 12 structure of the atom.
Following work by Rutherford and Marsden, a new model of the atom, called the ‘nuclear’ model, was suggested.
Describe the differences between the two models of the atom.
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Page 23 of 40 www.examqa.com Read this statement from a website. 13 Immediately after the ‘big bang’, at the start of the Universe,
there were only atoms of the element hydrogen (H).
Now there are over one hundred elements. Scientists think that all the elements on Earth are also present throughout the Universe.
(a) Explain how atoms of the element (He) are formed in a star.
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(b) Explain how atoms of very heavy elements, such as gold (Au), were formed.
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(c) Scientists have only examined a tiny fraction of the Universe.
What is the basis for scientists thinking that the elements found on Earth are present throughout the Universe?
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Page 24 of 40 www.examqa.com (a) Nuclear fuels and the wind are two of the energy sources used to generate electricity in the 14 UK.
Explain the advantages of using energy from nuclear fuels to generate electricity rather than using energy from the wind.
Include in your answer a brief description of the process used to generate electricity from nuclear fuels.
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(b) In the UK, most electricity is generated in power stations that emit carbon dioxide into the atmosphere. The impact of these power stations on the environment could be reduced by the increased use of 'carbon capture' technology.
Describe how 'carbon capture' would prevent the build-up of carbon dioxide in the atmosphere.
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Certain types of atom emit alpha, beta or gamma radiation. The radiation is emitted from the 15 centre of the atom.
(a) What name is given to the centre of an atom?
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Page 25 of 40 www.examqa.com (b) The sign below is used to warn people that a radiation source is being used in a laboratory.
Why is it important to warn people that a radiation source is being used?
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(c) Before using a radiation source, a teacher asked her class whether there was any way that she could reduce the amount of radiation that the source emitted. Three students each gave an answer to the teacher.
A B C
Which one of the students, A, B or C, is correct?
Write your answer in the box.
(1)
Page 26 of 40 www.examqa.com (d) The diagram shows the apparatus used by the teacher to demonstrate how one type of radiation is able to pass through lead.
One lead sheet, 2 mm thick, was placed between the source and the detector and a count rate was taken. Extra lead sheets were added. For each extra lead sheet, a new count rate was taken and recorded in the table.
Number of lead Count rate in counts sheets per minute
1 226
2 220
3 210
4 190
5 185
Which type of radiation was the source emitting: alpha, beta or gamma?
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Give the reason for your answer.
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Page 27 of 40 www.examqa.com (e) The diagram shows how a company detects any boxes left empty by an automatic filler.
When an empty box passes between the beta source and the detector, a buzzer sounds. A worker then removes the box from the conveyor belt.
(i) Why would this system not work if an alpha source were used instead of the beta source?
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Page 28 of 40 www.examqa.com (ii) The chart shows how the detector reading changes as boxes pass along the conveyor belt.
Which part of the chart, K, L, M or N, shows that an empty box is passing between the beta source and the detector?
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Give a reason for your answer.
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Page 29 of 40 www.examqa.com