Home
GCSE
Combined Science
OCR
Electronic structure

OCR GCSE Combined Science

Topic questions Atomic structure and the periodic table Electronic structure

Electronic structure

18 questions · 157 marks · about 3 hours

Electronic structure questions

TopicElectronic structure

Chemistry Paper 10 June 2025 Higher tier, Question 13 11 marks

Chlorine is an element found in Group 7 of the Periodic Table.

(a)

What are the elements in Group 7 called?

Tick (✓) one box.

$Question 13, shown as an image$

[1]

Reveal mark scheme

(b)

Why is chlorine found in Group 7 of the Periodic Table?

Use ideas about electron arrangement.

[1]

Reveal mark scheme

(c)

The diagram shows the reaction between a small piece of hot sodium and chlorine gas.

The sodium burns with a bright yellow flame and a white solid is produced.

(c)(i)

What is the name of the white solid made in the reaction?

[1]

Reveal mark scheme

(c)(ii)

A student thinks that the experiment is unsafe.

How could the experiment be improved to make it safe?

[1]

Reveal mark scheme

(c)(iii)

The metal spoon is made from an alloy of copper.

Suggest a property of this alloy which makes it suitable to use in the experiment.

[1]

Reveal mark scheme

(d)

The Group 7 elements can be placed into an order of reactivity by using displacement reactions.

The table shows the results of mixing three Group 7 elements, X, Y and Z, and solutions of their salts.

Key ✓ = reaction ✗ = no reaction

(d)(i)

Describe how the reactivity of the Group 7 elements changes going down the group.

Use the Periodic Table.

[1]

Reveal mark scheme

(d)(ii)

Which of the elements X, Y or Z is chlorine?

[1]

Reveal mark scheme

(d)(iii)

Which statements about the reactivity of the Group 7 elements are true, and which are false ?

Tick (✓) one box in each row.

[2]

Reveal mark scheme

(e)

This diagram shows how water is treated so it is safe to drink.

(e)(i)

At which stage, 1–4, is chlorine added to water?

[1]

Reveal mark scheme

(e)(ii)

Why is chlorine added to water?

[1]

Reveal mark scheme

Chemistry Paper 3 June 2024 Foundation tier, Question 17 12 marks

Lithium reacts with oxygen to form lithium oxide.

The symbols for lithium and oxygen on the Periodic Table are:

(a)

Explain how the positions of lithium and oxygen in the Periodic Table are used to decide that lithium is a metal and oxygen is a non-metal.

Use the Periodic Table on the Data Sheet.

[1]

Reveal mark scheme

(b)

Lithium reacts with oxygen to make lithium oxide.

Complete the balanced symbol equation for the reaction.

$Question 17, shown as an image$

[2]

Reveal mark scheme

(c)

Write the electron arrangement for an atom of lithium.

[1]

Reveal mark scheme

(d)

[2]

Reveal mark scheme

(e)

A student thinks that sodium reacts in a similar way to lithium.

Explain why they are correct.

Use the Periodic Table on the Data Sheet.

[1]

Reveal mark scheme

(f)

Lithium can exist as two isotopes.

Explain what isotope means.

[2]

Reveal mark scheme

(g)

Lithium can be added to aluminium to make an alloy. One alloy contains 2% lithium.

A student draws a diagram of the alloy.

(g)(i)

Calculate the percentage of lithium atoms in the alloy drawn by the student.

[2]

Reveal mark scheme

(g)(ii)

Suggest a reason why the student’s diagram is incorrect.

[1]

Reveal mark scheme

Chemistry Paper 9 June 2024 Higher tier, Question 11 12 marks

Lithium reacts with oxygen to form lithium oxide.

The symbols for lithium and oxygen on the Periodic Table are:

(a)

Explain how the positions of lithium and oxygen in the Periodic Table are used to decide that lithium is a metal and oxygen is a non-metal.

Use the Periodic Table on the Data Sheet.

[1]

Reveal mark scheme

(b)

Lithium reacts with oxygen to make lithium oxide.

Complete the balanced symbol equation for the reaction.

$Question 11, shown as an image$

[2]

Reveal mark scheme

(c)

Write the electron arrangement for an atom of lithium.

[1]

Reveal mark scheme

(d)

When an atom of lithium reacts with oxygen it forms a lithium ion, Li +. (d)

Describe how an atom of lithium forms a lithium ion.

[2]

Reveal mark scheme

(e)

A student thinks that sodium reacts in a similar way to lithium.

Explain why they are correct.

Use the Periodic Table on the Data Sheet.

[1]

Reveal mark scheme

(f)

Lithium can exist as two isotopes.

Explain what isotope means.

[2]

Reveal mark scheme

(g)

Lithium can be added to aluminium to make an alloy. One alloy contains 2% lithium.

A student draws a diagram of the alloy.

(g)(i)

Calculate the percentage of lithium atoms in the alloy drawn by the student.

[2]

Reveal mark scheme

(g)(ii)

Suggest a reason why the student’s diagram is incorrect.

[1]

Reveal mark scheme

Chemistry Paper 10 June 2024 Higher tier, Question 17 7 marks

The elements in Group 1 of the Periodic Table show trends in their properties.

The table shows the diameter of atoms and arrangement of electrons for the first three elements in Group 1.

Element	Diameter of atoms (m)	Arrangement of electrons
Lithium	3.04 × 10^–10	2, 1
Sodium	3.72 × 10^–10	2, 8, 1
Potassium	4.54 × 10^–10	2, 8, 8, 1

(a)

Describe and explain the trend in the diameter of atoms of the elements in Group 1.

[2]

Reveal mark scheme

(b)

Rubidium is the element below potassium in Group 1.

Predict the diameter of atoms of rubidium.

[1]

Reveal mark scheme

(c)

Describe and explain how the diameter of the atoms affects the reactivity of the elements in Group 1.

[4]

Reveal mark scheme

Chemistry Paper 3 June 2023 Foundation tier, Question 15 12 marks

Atoms of the same element can have different structures.

Fig. 15.1 shows the structure of two different atoms, Y and Z, of the same element.

Fig. 15.1

(a)

What name is given to different atoms of the same element such as Y and Z ?

[1]

Reveal mark scheme

(b)

Write the number of protons, neutrons and electrons in an atom of Z.

[2]

Reveal mark scheme

(c)

Write the mass number of an atom of Z.

[1]

Reveal mark scheme

(d)

Write the name of the element that contains atoms of Y and Z.

Use the Periodic Table.

[1]

Reveal mark scheme

(e)

(e)(i)

Complete Fig. 15.2 to show the arrangement of electrons in the ions.

[2]

Reveal mark scheme

(e)(ii)

What is the formula of the ionic compound formed when atoms of sodium react with atoms of Y ?

Tick (✓) one box.

$Question 15, shown as an image$

[1]

Reveal mark scheme

(e)(iii)

Why does sodium react with Y and Z in a similar way?

Tick (✓) one box.

$Question 15, shown as an image$

[1]

Reveal mark scheme

(e)(iv)

The ionic compound formed in Fig. 15.2 has a high melting point.

Explain why. Use ideas about structure and bonding.

[3]

Reveal mark scheme

Chemistry Paper 9 June 2023 Higher tier, Question 11 12 marks

Atoms of the same element can have different structures.

Fig. 11.1 shows the structure of two different atoms, Y and Z, of the same element.

Fig. 11.1

(a)

What name is given to different atoms of the same element such as Y and Z ?

[1]

Reveal mark scheme

(b)

Write the number of protons, neutrons and electrons in an atom of Z.

[2]

Reveal mark scheme

(c)

Write the mass number of an atom of Z.

[1]

Reveal mark scheme

(d)

Write the name of the element that contains atoms of Y and Z.

Use the Periodic Table.

[1]

Reveal mark scheme

(e)

(e)(i)

Complete Fig. 11.2 to show the arrangement of electrons in the ions.

[2]

Reveal mark scheme

(e)(ii)

What is the formula of the ionic compound formed when atoms of sodium react with atoms of Y ?

Tick (✓) one box.

$Question 11, shown as an image$

[1]

Reveal mark scheme

(e)(iii)

Why does sodium react with Y and Z in a similar way?

Tick (✓) one box.

$Question 11, shown as an image$

[1]

Reveal mark scheme

(e)(iv)

The ionic compound formed in Fig. 11.2 has a high melting point.

Explain why. Use ideas about structure and bonding.

[3]

Reveal mark scheme

Chemistry Paper 3 June 2022 Foundation tier, Question 12 14 marks

Atoms are made from protons, neutrons and electrons.

(a)

The table shows the relative mass and relative charge of a proton, neutron and electron.

Particle	Relative mass	Relative charge
proton	1	....................................
neutron	....................................	0
electron		....................................

Complete the table.

Write your answers in the three boxes in the table.

[3]

Reveal mark scheme

(b)

[1]

Reveal mark scheme

(c)

An atom of helium contains:

• 2 protons

• 2 neutrons

• 2 electrons.

Draw a labelled diagram to show the arrangement of protons, neutrons and electrons in an atom of helium.

[3]

Reveal mark scheme

(d)

(d)(i)

Which two elements are in Group 1 of the Periodic Table?

[1]

Reveal mark scheme

(d)(ii)

Which element is in Period 4 of the Periodic Table?

[1]

Reveal mark scheme

(d)(iii)

Which element has a mass number of 12?

[1]

Reveal mark scheme

(d)(iv)

Which two elements are isotopes?

[1]

Reveal mark scheme

(d)(v)

Which element forms an ion with a 2+ charge?

[1]

Reveal mark scheme

(e)

Aluminium forms an Al³⁺ ion and chlorine forms a Cl^– ion. (e)

Three students write down the formula of aluminium chloride.

Student A: A l C l

Student B: Al Cl₃

Student C: Al₃Cl

Which student is correct?

Explain your answer.

[2]

Reveal mark scheme

Chemistry Paper 4 June 2022 Foundation tier, Question 16 12 marks

This question is about the Group 7 elements.

Table 16.1 shows some information about the Group 7 elements.

Table 16.1

Element	Molecular formula	Appearance at room temperature	Size of molecule (pm)	Boiling point (°C)
Fluorine	F₂	pale-yellow gas	128	–188
Chlorine	Cl₂	green gas	204	–34
Bromine	Br₂	orange-brown liquid	240
Iodine	I₂	grey-black solid	278	184
Astatine	At₂	.............................................	300	350

(a)

Complete the table by predicting the appearance of astatine at room temperature.

Write your answer in the box in Table 16.1.

[1]

Reveal mark scheme

(b)

The sizes of the molecules are measured in picometres (pm).

$Question 16, shown as an image$

What is the size of a fluorine molecule in metres (m)?

Tick (✓) one box.

[1]

Reveal mark scheme

(c)

[1]

Reveal mark scheme

(d)(i)

Use Table 16.1 to complete the x axis and plot a line graph of the boiling points of fluorine, chlorine, iodine and astatine against the size of their molecules.

Draw a line of best fit.

[4]

Reveal mark scheme

(d)(ii)

Use your graph to predict the boiling point of bromine.

Table 16.1 is repeated below.

Table 16.1

Element	Molecular formula	Appearance at room temperature	Size of molecule (pm)	Boiling point (°C)
Fluorine	F₂	pale-yellow gas	128	–188
Chlorine	Cl₂	green gas	204	–34
Bromine	Br₂	orange-brown liquid	240
Iodine	I₂	grey-black solid	278	184
Astatine	At₂		300	350

[1]

Reveal mark scheme

(e)

A student thinks that fluorine molecules have the weakest intermolecular forces.

Give two reasons why they are correct.

Use data from Table 16.1.

[2]

Reveal mark scheme

(f)

Describe one similarity and one difference in the arrangement of electrons in atoms of fluorine and chlorine.

Similarity........

Difference........

[2]

Reveal mark scheme

Chemistry Paper 9 June 2022 Higher tier, Question 12 10 marks

Potassium chloride, KC l, is an ionic compound.

It is made from potassium ions, K +, and chloride ions, C l –.

(a)

Explain why potassium is found in Group 1 of the Periodic Table.

Use ideas about the arrangement of electrons in an atom of potassium.

[1]

Reveal mark scheme

(b)

Explain how an atom of potassium reacts with an atom of chlorine to make potassium chloride.

[2]

Reveal mark scheme

(c)

A student electrolyses potassium chloride.

The diagram shows the equipment they use.

$Question 12, shown as an image$

Describe and explain two ways the student could change the experiment to make it work.

[4]

Reveal mark scheme

(d)

In the successful electrolysis of potassium chloride, potassium is made at the cathode.

Explain how potassium atoms are made from potassium ions.

[3]

Reveal mark scheme

Chemistry Paper 9 June 2022 Higher tier, Question 14 18 marks

Calcium is a metal found in Group 2 of the Periodic Table.

(a)

Draw the arrangement of electrons in an atom of calcium.

[1]

Reveal mark scheme

(b)

Calcium is a metal which can conduct electricity.

Describe the structure and bonding in a metal and explain why metals can conduct electricity.

You can include a diagram in your answer.

[4]

Reveal mark scheme

(c)

Calcium reacts with water to form a solution of calcium hydroxide, Ca(OH)₂, and hydrogen.

(c)(i)

Write the balanced symbol equation for the reaction of calcium with water.

Include state symbols in your equation.

[3]

Reveal mark scheme

(c)(ii)

A solution of calcium hydroxide is also called limewater.

Name the gas limewater is used as a test for.

[1]

Reveal mark scheme

(d)

(d)(i)

Calculate the number of moles in 1.88 g of calcium hydroxide.

Give your answer to 2 significant figures.

Relative atomic mass (A_r): H = 1.0 O = 16.0 Ca = 40.1

[3]

Reveal mark scheme

(d)(ii)

Use your answer to part (d)(i) to calculate the concentration of calcium hydroxide in the solution formed.

Give your answer in mol / dm³.

Concentration of solution =........ mol / dm³

[2]

Reveal mark scheme

(e)

A student adds an excess of dilute hydrochloric acid, HC l, to a solution of calcium hydroxide, Ca(OH)₂.

(e)(i)

Write the balanced ionic equation for the reaction of dilute hydrochloric acid and a solution of calcium hydroxide.

[1]

Reveal mark scheme

(e)(ii)

Describe and explain how the pH of the solution of calcium hydroxide changes as the dilute hydrochloric acid is added until it is in excess.

[3]

Reveal mark scheme

Chemistry Paper 10 June 2022 Higher tier, Question 11 12 marks

This question is about the Group 7 elements.

Table 11.1 shows some information about the Group 7 elements.

Table 11.1

Element	Molecular formula	Appearance at room temperature	Size of molecule (pm)	Boiling point (°C)
Fluorine	F₂	pale-yellow gas	128	–188
Chlorine	Cl₂	green gas	204	–34
Bromine	Br₂	orange-brown liquid	240
Iodine	I₂	grey-black solid	278	184
Astatine	At₂	.............................................	300	350

(a)

Complete the table by predicting the appearance of astatine at room temperature.

Write your answer in the box in Table 11.1.

[1]

Reveal mark scheme

(b)

The sizes of the molecules are measured in picometres (pm).

$Question 11, shown as an image$

What is the size of a fluorine molecule in metres (m)?

Tick (✓) one box.

[1]

Reveal mark scheme

(c)

Which element has a molecule that is closest to twice the size of a molecule of fluorine?

Tick (✓) one box.

$Question 11, shown as an image$

[1]

Reveal mark scheme

(d)(i)

Use Table 11.1 to complete the x axis and plot a line graph of the boiling points of fluorine, chlorine, iodine and astatine against the size of their molecules.

Draw a line of best fit.

[4]

Reveal mark scheme

(d)(ii)

Use your graph to predict the boiling point of bromine.

Table 11.1 is repeated below.

Table 11.1

Element	Molecular formula	Appearance at room temperature	Size of molecule (pm)	Boiling point (°C)
Fluorine	F₂	pale-yellow gas	128	–188
Chlorine	Cl₂	green gas	204	–34
Bromine	Br₂	orange-brown liquid	240
Iodine	I₂	grey-black solid	278	184
Astatine	At₂		300	350

[1]

Reveal mark scheme

(e)

A student thinks that fluorine molecules have the weakest intermolecular forces.

Give two reasons why they are correct.

Use data from Table 11.1.

[2]

Reveal mark scheme

(f)

Describe one similarity and one difference in the arrangement of electrons in atoms of fluorine and chlorine.

[2]

Reveal mark scheme

Chemistry Paper 3 November 2021 Foundation tier, Question 1 1 mark

[1]

Reveal mark scheme

Chemistry Paper 3 November 2021 Foundation tier, Question 9 1 mark

An atom of an element forms an ion with the formula X^2–.

Which Group of the Periodic Table is the element found in?

A Group 0

B Group 2

C Group 6

D Group 7

$Question 9, shown as an image$

[1]

Reveal mark scheme

Chemistry Paper 3 November 2021 Foundation tier, Question 16 6 marks

16* Helium and neon are the first two elements in Group 0 of the Periodic Table.

Look at the symbols for helium and neon.

Describe the similarities and differences in the atomic structures of helium and neon.

[6]

Reveal mark scheme

Chemistry Paper 9 November 2021 Higher tier, Question 1 1 mark

An atom of an element forms an ion with the formula X^2–. 1

Which Group of the Periodic Table is this element found in?

A Group 0

B Group 2

C Group 6

D Group 7

$Question 1, shown as an image$

[1]

Reveal mark scheme

Chemistry Paper 3 June 2019 Foundation tier, Question 11 9 marks

Atoms are made of particles called protons, neutrons and electrons.

(a)

Complete the table to show the relative charges of protons, neutrons and electrons.

Particle	Relative charge
Proton	............................
Neutron	0
Electron	............................

[2]

Reveal mark scheme

(b)

Sodium is a metal in the Periodic Table.

(b)(i)

[3]

Reveal mark scheme

(b)(ii)

Sodium is an example of an atom that can form an ion.

Describe what happens to a sodium atom when it becomes an ion.

[1]

Reveal mark scheme

(c)

Look at this statement about the Periodic Table.

‘Atoms are placed in groups according to the total number of electrons they have.’

Explain why this statement is incorrect.

[1]

Reveal mark scheme

(d)

A new element has been discovered and has these properties:

• a high melting point

• reacts with oxygen to form oxides

• conducts electricity

• solid at room temperature.

Suggest what type of bonding the new element has.

Explain your answer.

[2]

Reveal mark scheme

Chemistry Paper 4 June 2018 Foundation tier, Question 3 1 mark

Look at the table.

	State at room temperature	Electronic structure
A	Gas	2.7
B	Gas	2.8.7
C	Liquid	2.8.7
D	Solid	2.7

Which row in the table has the correct information about chlorine?

$Question 3, shown as an image$

[1]

Reveal mark scheme

Chemistry Paper 4 June 2018 Foundation tier, Question 16 6 marks

[6]

Reveal mark scheme

Report a problem with a question on this page

Question

What is wrong?

Text or a picture is cut off or split Something on the paper is not here The text does not read properly The marks are wrong Something else

Goes to whoever maintains the question split. No account needed and nothing is published on this page.

Memes

Certified Combined Science memes. Peer-reviewed by nobody.

Laugh now. Cry in the exam hall later. Then come back and do a past paper.

Revise all three sciences

Just revise the fun one

Me the night before the chemistry paper

Knowing it's three sciences

Knowing which teacher does which

Remembering which equations are given

Remembering which science you're actually sitting today

Science enlightenment, combined

Mum 💖

which science is it today? 🥰

all of them somehow

go on genius!!! 💪

📱 Screen time this week · YouTube6h 21m

None of them were revised

Combined Science starter pack

Goggles worn on foreheadBunsen on the yellow flamePractical write-up, half doneThis website

Three sciences, four items

Electronic structure

Electronic structure questions

OCR J250 Electronic structure 18 questions

Chemistry Paper 10 June 2025 Higher tier, Question 13 Higher Chemistry Paper 10 · June 2025 · Question 13 11 marks

Chemistry Paper 3 June 2024 Foundation tier, Question 17 Foundation Chemistry Paper 3 · June 2024 · Question 17 12 marks

Chemistry Paper 9 June 2024 Higher tier, Question 11 Higher Chemistry Paper 9 · June 2024 · Question 11 12 marks

Chemistry Paper 10 June 2024 Higher tier, Question 17 Higher Chemistry Paper 10 · June 2024 · Question 17 7 marks

Chemistry Paper 3 June 2023 Foundation tier, Question 15 Foundation Chemistry Paper 3 · June 2023 · Question 15 12 marks

Chemistry Paper 9 June 2023 Higher tier, Question 11 Higher Chemistry Paper 9 · June 2023 · Question 11 12 marks

Chemistry Paper 3 June 2022 Foundation tier, Question 12 Foundation Chemistry Paper 3 · June 2022 · Question 12 14 marks

Chemistry Paper 4 June 2022 Foundation tier, Question 16 Foundation Chemistry Paper 4 · June 2022 · Question 16 12 marks

Chemistry Paper 9 June 2022 Higher tier, Question 12 Higher Chemistry Paper 9 · June 2022 · Question 12 10 marks

Chemistry Paper 9 June 2022 Higher tier, Question 14 Higher Chemistry Paper 9 · June 2022 · Question 14 18 marks

Chemistry Paper 10 June 2022 Higher tier, Question 11 Higher Chemistry Paper 10 · June 2022 · Question 11 12 marks

Chemistry Paper 3 November 2021 Foundation tier, Question 1 Foundation Chemistry Paper 3 · November 2021 · Question 1 1 mark

Chemistry Paper 3 November 2021 Foundation tier, Question 9 Foundation Chemistry Paper 3 · November 2021 · Question 9 1 mark

Chemistry Paper 3 November 2021 Foundation tier, Question 16 Foundation Chemistry Paper 3 · November 2021 · Question 16 6 marks

Chemistry Paper 9 November 2021 Higher tier, Question 1 Higher Chemistry Paper 9 · November 2021 · Question 1 1 mark

Chemistry Paper 3 June 2019 Foundation tier, Question 11 Foundation Chemistry Paper 3 · June 2019 · Question 11 9 marks

Chemistry Paper 4 June 2018 Foundation tier, Question 3 Foundation Chemistry Paper 4 · June 2018 · Question 3 1 mark

Chemistry Paper 4 June 2018 Foundation tier, Question 16 Foundation Chemistry Paper 4 · June 2018 · Question 16 6 marks

Certified Combined Science memes. Peer-reviewed by nobody.

Chemistry Paper 10 June 2025 Higher tier, Question 13 11 marks

Chemistry Paper 3 June 2024 Foundation tier, Question 17 12 marks

Chemistry Paper 9 June 2024 Higher tier, Question 11 12 marks

Chemistry Paper 10 June 2024 Higher tier, Question 17 7 marks

Chemistry Paper 3 June 2023 Foundation tier, Question 15 12 marks

Chemistry Paper 9 June 2023 Higher tier, Question 11 12 marks

Chemistry Paper 3 June 2022 Foundation tier, Question 12 14 marks

Chemistry Paper 4 June 2022 Foundation tier, Question 16 12 marks

Chemistry Paper 9 June 2022 Higher tier, Question 12 10 marks

Chemistry Paper 9 June 2022 Higher tier, Question 14 18 marks

Chemistry Paper 10 June 2022 Higher tier, Question 11 12 marks

Chemistry Paper 3 November 2021 Foundation tier, Question 1 1 mark

Chemistry Paper 3 November 2021 Foundation tier, Question 9 1 mark

Chemistry Paper 3 November 2021 Foundation tier, Question 16 6 marks

Chemistry Paper 9 November 2021 Higher tier, Question 1 1 mark

Chemistry Paper 3 June 2019 Foundation tier, Question 11 9 marks

Chemistry Paper 4 June 2018 Foundation tier, Question 3 1 mark

Chemistry Paper 4 June 2018 Foundation tier, Question 16 6 marks