Simple recall questions are usually worth 1 mark. They are often have command words like 'give', 'state', 'name' or 'identify'. Some questions may ask you to state two things, rather than just one, and will be worth 2 marks.
Structured questions, with command words such as 'describe' or 'explain', will be worth 2 or more marks:
More complex structured questions will be worth three to five marks. They include questions with complex descriptions and explanations, questions in which you need to compare and contrast two different things, or calculations with several stages.
The mark schemes given here may show answers as bullet points. This is to show clearly how a mark can be obtained. However, it is important that your answer is written in a logical, linked way.
Questions courtesy of Eduqas.
The following equation shows a nuclear reaction.
a) The hydrogen isotopes have to move very quickly for this reaction to take place and controlling this reaction on Earth is difficult. Complete the following sentences. [2 marks]
i) The hydrogen isotopes are made to collide with high energies by making the gas ______ .
ii) The problem this causes is ______ .
b) Choose the correct word from the brackets in each sentence below. [3 marks]
i) The reactants are isotopes of [ hydrogen / helium / neutrons ].
ii) The reactants have the same numbers of [ neutrons / protons / nucleons ].
iii) This reaction is an example of a [ fusion / fission / chain ] reaction.
c) Give two reasons why this reaction is likely to be important in the future. [2 marks]
a) i) very hot/at a high temperature 
ii) the container is in danger of melting/difficult to achieve such high temperatures/requires high energy 
b) i) hydrogen 
ii) protons 
iii) fusion 
c) Any two from:
Nuclear medicine uses radioisotopes which emit radiation from within the body. One tracer uses iodine, which is injected into the body to treat the thyroid gland. The table shows four isotopes of iodine.
|Form of iodine||Radiation emitted||Half-life|
|iodine-129||beta and gamma||15,000,000 years|
|iodine-131||beta and gamma||8.4 days|
a) Iodine-129 emits both beta and gamma radiation. Describe the nature of these types of radiation. [2 marks]
b) The table shows that the half-life of iodine-125 is 59.4 days. State what this means. [2 marks]
c) Use the data to explain why iodine-131 is the most suitable form of iodine for treating thyroid cancer. [2 marks]
a) Beta - high energy/fast moving electron 
Gamma - electromagnetic wave 
b) The activity/mass/number of unstable nuclei  halves in 59.4 days .
c) It has a suitable half-life/not too long a half-life/not too short a half-life  so it doesn't decay too quickly .