Six-mark questions
Six-mark questions are extended open response questions. These require longer answers than the structured questions. It is wise to plan your answer rather than rushing straight into it, otherwise you may stray away from the key points.
To gain full marks, you need to:
- support explanations using scientific knowledge and understanding
- use appropriate scientific words and terms
- write clearly and link ideas in a logical way
- maintain a sustained line of reasoning, rather than getting lost or bogged down
Six-mark questions often use these command words:
- Describe - you need to give an account but no reason
- Explain - you must give reasons or explanations
- Devise - you must plan or invent a procedure using your scientific knowledge and understanding
- Evaluate - you must review information, including identifying strengths and weaknesses, and make a supported conclusion
Six-mark questions may be synoptic questions. These questions bring together ideas from two or more topics. For example, a question about fertilisers could include ideas about covalent substances, acids and alkalis, chemical calculations, and effects on the environment.
Remember that this topic, Key concepts in Chemistry, is tested in both paper 1 and paper 2.
The answers shown here give marking points as bullet points. You do not usually need to include all of them to gain six marks, but you do need to write in full sentences, linking them logically and clearly.
Writing six-mark answers with Dr Alex Lathbridge
Listen to the full series on 大象传媒 Sounds.
How to write six-mark answers in your science GCSE exams.
Sample question 1 - Foundation
Question
The table shows the ability of different substances to conduct electricity.
| Substance | Conducts electricity? |
| Solid calcium chloride | No |
| Molten calcium chloride | Yes |
| Diamond | No |
| Zinc | Yes |
| Substance | Solid calcium chloride |
|---|---|
| Conducts electricity? | No |
| Substance | Molten calcium chloride |
|---|---|
| Conducts electricity? | Yes |
| Substance | Diamond |
|---|---|
| Conducts electricity? | No |
| Substance | Zinc |
|---|---|
| Conducts electricity? | Yes |
Explain these results by referring to the structures of the substances. [6 marks]
Edexcel question courtesy of Pearson Education Ltd.
Your answer should include the following:
- Solid calcium chloride contains ions/cations/anions which are charged particles.
- Solid calcium chloride does not conduct because charged particles are not free to move because they are held together by strong electrostatic forces/ionic bonds in lattice.
- Molten calcium chloride solution conducts because ions/cations/anions are present which are charged particles and are free to move.
- The ions have separated, and move to the electrode of opposite charge.
- Diamond does not conduct because it is a giant molecular covalent with no free electrons.
- Outer electrons of carbon atoms are used in bonding.
- Zinc metallic structure consists of delocalised free electrons which can move between layers of metals atoms/cations.
[6]
Sample question 2 - Higher
Question
Describe the structure of an atom, including properties of its subatomic particles. [6 marks]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
Your answer should include the following:
- Nucleus surrounded by electrons.
- Electrons arranged in shells.
- Nucleus contains protons and neutrons.
- Number of protons and electrons is the same.
- Protons are positively charged, electrons are negatively charged, neutrons are neutral.
- Overall charge on an atom is zero.
- Protons and neutrons have the same mass, electrons are much lighter particles.
- Most of the mass is concentrated in the nucleus.
- Nucleus is very small compared to the overall size of an atom.
[6]
Sample question 3 - Foundation
Question
The table shows the melting points of different substances.
| Substance | Melting point |
| Sodium chloride | 801掳颁 |
| Water | 0掳颁 |
| Diamond | 3730掳颁 |
| Substance | Sodium chloride |
|---|---|
| Melting point | 801掳颁 |
| Substance | Water |
|---|---|
| Melting point | 0掳颁 |
| Substance | Diamond |
|---|---|
| Melting point | 3730掳颁 |
Explain these results by referring to the structures of the substances. [6 marks]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
Your answer should include the following:
- Sodium chloride contains ions in a regular lattice.
- There are electrostatic forces of attraction between oppositely charged ions.
- The forces/ionic bonds are strong.
- A lot of energy is needed to overcome/break these forces/bonds.
- Water exists as simple molecules.
- There are weak intermolecular forces between molecules.
- Less energy needed to overcome these forces.
- Diamond exists as giant molecules.
- There are covalent bonds between atoms.
- Many strong covalent bonds.
- A large amount of energy is needed to break bonds.
[6]
Sample question 4 - Higher
Question
Describe how the arrangement of elements in the periodic table is related to the atomic structure of their atoms. [6 marks]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
Your answer should include the following:
- In the periodic table the elements are arranged in order of increasing atomic number/proton number.
- The horizontal rows are called periods.
- The atomic number of the elements increases steadily across a period.
- Elements in the same period have the same number of electron shells.
- The vertical columns are groups.
- Elements in the same group have similar chemical properties.
- Atoms of elements in the same group have the same number of outer electrons.
- The number of outer electrons is equal to the group number.
- The number of occupied electron shells increases down a group.
[6]
More guides on this topic
- Equations and formulae - Edexcel
- Hazards and risks - Edexcel
- Atomic structure - Edexcel
- The periodic table - Edexcel
- Ionic compounds - Edexcel
- Simple molecular substances - Edexcel
- Giant covalent substances - Edexcel
- Metals and non-metals - Edexcel
- Chemistry calculations - Edexcel
- Mole calculations (higher) - Edexcel