Questions Q1. The diagram represents an atom of beryllium (Be). (i) State the name of the particle labelled X. (1)

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1 Questions Q1. The diagram represents an atom of beryllium (Be). (i) State the name of the particle labelled X. (ii) Which of these is the correct symbol for this nucleus of beryllium? Put a cross ( ) in the box next to your answer. (iii) Explain how a beryllium atom can become a positive ion. (2)

2 Q2. Everyone is exposed to background radiation. Some of this radiation comes from natural sources. (i) One example of a source of background radiation that does not occur naturally is radiotherapy. State one other source of background radiation that does not occur naturally. (ii) Radon gas is a natural source of background radiation. In some parts of the country, a lot of the background radiation comes from radon gas. Explain why there is no radon gas in some other parts of the country. (2) Q3. Describe one other use of a radioactive source. (2)

3 Q4. Everyone is exposed to background radiation. Some of this radiation comes from natural sources. (a) (i) One example of a source of background radiation that does not occur naturally is radiotherapy. State one other source of background radiation that does not occur naturally. (ii) Radon gas is a natural source of background radiation. In some parts of the country, a lot of the background radiation comes from radon gas. Explain why there is no radon gas in some other parts of the country. (2) (b) Technetium-99 is one of the radioactive isotopes in nuclear waste. The graph shows the decay curve for technetium-99. (i) Use the graph to show that the half-life of technetium-99 is about years. (2) (ii) Technetium-99 emits beta particles. Give one reason that beta particles can cause harm to people.

4 *(c) There are many radioactive isotopes in nuclear waste. Technetium-99 is just one of these isotopes. People are worried about how we should deal with nuclear waste. Explain why it is difficult to deal with nuclear waste safely. (6) (Total for Question is 12 marks) Examiner's Report Q1. (i) Most ( 86% ) correctly gave neutron as the name of X. (iii) Only 26% correctly explained that the atom should lose an electron. Too many tried to add or remove a proton or even a neutron to ionise the beryllium atom. Credit was given for attempting to alter the total charge. This response was awarded one mark Candidate has the correct idea of charge transfer. This response gained both marks.

5 Candidate states that beryllium must lose an electron.

6 Q2. (i) Many candidates did not appreciate that the question asked for a source of background radiation that does not occur naturally, which ruled out cosmic rays, food, etc. This question also showed that a significant number of candidates believe that chemotherapy is radioactive rather than being treatment by drugs. The most frequently seen correct answer was X-ray (machines). (ii) The fact that radon gas originates in granite rocks was known by surprisingly few candidates. However, if the origin was known then it easily explained why some parts of the country did not have radon and this gave candidates the opportunity of scoring both marks. Power plants were quite often believed to be the origin of radon gas. No marks were awarded. This is a rare example where 1 mark was awarded. The candidate knows the origin of radon gas but does not explain why it is not found in some parts of the country.

7 Q3. No Examiner's Report available for this question

8 Q4. (a)(i) Many candidates did not appreciate that the question asked for a source of background radiation that does not occur naturally, which ruled out cosmic rays, food, etc. This question also showed that a significant number of candidates believe that chemotherapy is radioactive rather than being treatment by drugs. The most frequently seen correct answer was X-ray (machines). (a)(ii) The fact that radon gas originates in granite rocks was known by surprisingly few candidates. However, if the origin was known then it easily explained why some parts of the country did not have radon and this gave candidates the opportunity of scoring both marks. Power plants were quite often believed to be the origin of radon gas. No marks were awarded. This is a rare example where 1 mark was awarded. The candidate knows the origin of radon gas but does not explain why it is not found in some parts of the country.

9 (b)(i) The majority of candidates were able to score 2 marks. It was unusual for candidates to draw two horizontal lines to the curve at appropriate values of the activity and then show that by taking lines from the curve to the y-axis that the half-life was about years. Most candidates took half the activity between 700 Bq and 800 Bq and drew a horizontal line to meet the curve and then a vertical line to the x-axis indicating the half-life. This answer gained 2 marks for showing the half-life is about years, having started the horizontal line from 760 Bq.

10 This answer gives additional information indicating that half the initial activity is used to determine the half-life and was awarded 2 marks.

11 This response only scored 1 mark, as the line from the curve to the x-axis does not meet the line from the y-axis and gives a value which is out of tolerance. Results Plus: Examiner Tip Ensure that lines are drawn accurately and if an incorrect line is replaced indicate clearly which line is to be marked. (b)(ii) A disappointing number of candidates could not offer one of the acceptable answers, either because they gave a general description of the penetration of beta particles rather that relating the answer to people (as requested in the question) or their answers were incomplete.

12 This answer needs to be extended to explain what is likely to be mutated. The mark was not awarded. Results Plus: Examiner Tip Make sure your answer provides a complete explanation. An acceptable answer would be that beta particles can cause cancer. This answer does little more than repeat the stem of the question therefore the mark was not awarded. This answer is not related to people and therefore did not score a mark. (c) Although there has been an improvement in the way candidates answer this type of question, many of them struggled to answer it in a coherent way. The best responses mentioned one or more properties of nuclear waste and then linked them to a problem caused as a result of these properties before going on to suggest one or more solutions. Less able candidates mentioned that nuclear waste was harmful to humans or named a method for dealing with it. It appeared that some candidates may have felt that they needed to fill all the space available because they repeated the same point in different words.

13 This answer makes the point that nuclear waste is buried under ground. This is a Level 1 response and was awarded 2 marks. This answer includes the point that nuclear waste has a long half-life. One isolated point is made; this is a Level 1 response and it scored 2 marks.

14 This answer gives detail on why it is difficult to get rid of nuclear waste, the problems it can cause and it also gives a property of nuclear waste, ie that it has a long half-life. It is a coherent account linking facts. It is a Level 3 response and was awarded all 6 marks. Results Plus: Examiner Tip Try to link facts together using 'because ' or 'therefore'.

15 This answer explains how nuclear waste can be treated and links this to the harm it can cause. It is a Level 2 response and was awarded 4 marks. Mark Scheme Q1. Answer Acceptable answers (i) Neutron(s) Accept phonetic spellings eg newtron(s) or neutron(s) Reject newtons (ii) D 9 Be 4 (iii) A explanation linking Gains/loses charge the following points Gains an electron = Charge/electron 1mark Loses (an) transfer electron(s) gains both marks Correct transfer Award 1 mark for detail gaining a proton as idea of gains charge Mark (2)

16 Q2. (i) (ii) Answer any one of X-ray (machines) / smoke alarms/ nuclear/ radioactive waste an explanation linking: comes from granite / rocks none/ less of these (rocks) in some areas Acceptable answers nuclear weapons (tests) nuclear power plants (medical) tracers/technetium in some areas/cornwall/aber deen the second mark is dependent on the first. Mark (2) Q3. Question Number Answer Acceptable answers Mark A description including the following points clear statement of application detail about how it works / type of radiation used / purpose e.g. in a smoke alarm alpha source is used gamma rays are used to kill cancer cells food is irradiated to make it last longer check the thickness of paper by measuring how much radiation gets through it (2)

17 Q4. (a)(i) (a)(ii) (b)(i) (b)(ii) Answer any one of X-ray (machines) / smoke alarms/ nuclear/ radioactive waste an explanation linking: comes from granite / rocks none/ less of these (rocks) in some areas suitable lines on graph to show halving after about years (2) horizontal line at 750 +or 50 Bq on y-axis to curve meeting (by eye) vertical line from x-axis between 190,000 years and 230,000 years any one of penetrates/passes through the skin ionises damages tissue/ cells/dna mutates cells/dna causes cancer Acceptable answers nuclear weapons (tests) nuclear power plants (medical) tracers/technetium in some areas/cornwall/aber deen the second mark is dependent on the first. use of data from graph to show halving after about years 1500/2 =750(Bq) or 1600/2=800(Bq) gives a half-life of 210,000 +or (years) Indicative Content Mark (2) (2) Total marks for question = 12 Mark QWC *(c) an explanation which may include some of the following points: properties of nuclear waste radioactivity is dangerous some isotopes in nuclear waste have long half-lives/radioactive for thousands of years products of fission are warm identified radiation (6)

18 from nuclear waste e.g alpha, beta, gamma problems caused by nuclear waste leakage of radioactivity contamination of ground/sea water/lakes /rivers contamination of crops/fish/animals/dri nking water harm to humans/cancer/radia tion poisoning/ damage to cells/mutation of cells or DNA difficulty in transporting safely/ stolen by terrorists fears of local people solutions for dealing with nuclear waste safely long term storage, underground /under the sea radiation shielding, lead/steel/concrete/ containers, sealed in glass. human safety, radiation suits, using tongs/lead jackets safe location, away from people/remote areas/sea cooling, ponds information to persuade local people of safety Level 0 No rewardable content a limited explanation mentioning at least one point, but without linking, e.g. radioactivity is dangerous ; nuclear waste should be stored underground ; terrorists might steal nuclear waste; the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy a simple explanation mentioning two points with an appropriate linkage e.g.

19 3 5-6 nuclear waste is dangerous and it must be stored underground ; the isotopes in nuclear waste have long half-lives so they must be stored for a long time; the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy a detailed explanation mentioning a range of points with appropriate linkages e.g. gamma rays from nuclear waste causes damage to cells so it must be stored away from where people live ; the isotopes in nuclear waste have long half-lives so they must be stored underground or in remote areas; the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors