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Edexcel IGCSE Chemistry

Topic questions Atomic structure and the periodic table Subatomic particles

Subatomic particles

20 questions · 143 marks · about 2.5 hours

Subatomic particles questions

Edexcel 4CH1 Subatomic particles 20 questions

Chemistry Paper 1 June 2025, Question 1 8 marks

The diagram represents an atom of an element.

Figure for question 1
(a)

Label the three subatomic particles on the diagram.

[3]
Reveal mark scheme Mark scheme for question 1(a)
(b)

Use information from the diagram to complete the table for this element.

Figure for question 1
[4]
Reveal mark scheme Mark scheme for question 1(b)
(c)

Give the name of this element.

[1]
Reveal mark scheme Mark scheme for question 1(c)

Chemistry Paper 2 November 2024, Question 1 7 marks

The table shows the composition of five species that are either atoms or ions.

SpeciesNumber of protonsNumber of neutronsNumber of electrons
A101
B333
C343
D91010
E131413
(a)

Use the table to answer these questions.

You may use each letter once, more than once, or not at all.

(a)(i)

Give the letter of the species that is a negative ion.

[1]
Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)

Give the letter of the species that has a full outer shell of electrons.

[1]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(a)(iii)

Give the letter of the species that has an atomic number equal to its mass number.

[1]
Reveal mark scheme Mark scheme for question 1(a)(iii)
(b)

Explain why species B and C are atoms of the same element with identical chemical properties.

[2]
Reveal mark scheme Mark scheme for question 1(b)
(c)

A proton has a mass of 1.6726maths symbol10–24g.

A neutron has a mass of 1.6740maths symbol10–24g.

Calculate the mass, in grams, of the nucleus of an atom of species C.

[2]
Reveal mark scheme Mark scheme for question 1(c)

Chemistry Paper 1 June 2024 (R), Question 1 5 marks

This question is about atomic structure.

(a)

The table shows the number of protons, neutrons and electrons in five species, V, W, X, Y and Z.

The letters represent the species but are not symbols from the Periodic Table.

SpeciesNumber of protonsNumber of neutronsNumber of electrons
V293827
W121212
X91010
Y668
Z7710

Choose letters from the table to answer these questions.

Each letter may be used once, more than once or not at all.

(a)(i)

Which species is an atom?

[1]
Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)

Which species is an ion with a positive charge?

[1]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(a)(iii)

Which species is an ion with a 3− charge?

[1]
Reveal mark scheme Mark scheme for question 1(a)(iii)
(b)
(b)(i)

State what is meant by the term atomic number.

[1]
Reveal mark scheme Mark scheme for question 1(b)(i)
(b)(ii)

State what is meant by the term mass number.

[1]
Reveal mark scheme Mark scheme for question 1(b)(ii)

Chemistry Paper 2 June 2024 (R), Question 2 6 marks

(a)

The diagram represents an atom of an element.

Figure for question 2
(a)(i)

What is the name of the particle labelled W?

Question 2, shown as an image
[1]
Reveal mark scheme Mark scheme for question 2(a)(i)
(a)(ii)

What is the mass number of this atom?

Question 2, shown as an image
[1]
Reveal mark scheme Mark scheme for question 2(a)(ii)
(b)

These are the symbols for the two isotopes of lithium.

Question 2, shown as an image
(b)(i)

In terms of sub-atomic particles, give one similarity and one difference between the two isotopes.

similarity

[2]
Reveal mark scheme Mark scheme for question 2(b)(i)
(b)(ii)

difference

A sample of lithium contains 7.5% of63Li and 92.5% of73Li

Calculate the relative atomic mass (Ar) of this sample of lithium.

[2]
Reveal mark scheme Mark scheme for question 2(b)(ii)

Chemistry Paper 1 November 2023, Question 2 10 marks

(a)

Table 1 shows some relative masses and charges of subatomic particles.

Complete table 1 by giving the missing information.

Figure for question 2
[2]
Reveal mark scheme Mark scheme for question 2(a)
(b)

Table 2 gives the number of protons, neutrons and electrons in atoms and ions of some elements.

The letters are not the symbols of the elements.

Figure for question 2
(b)(i)

What is the atomic number of P in table 2?

Question 2, shown as an image
[1]
Reveal mark scheme Mark scheme for question 2(b)(i)
(b)(ii)

What is the mass number of U in table 2?

Question 2, shown as an image
[1]
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(b)(iii)

Give the letter in table 2 that represents an element in Group 5 of the Periodic Table.

[1]
Reveal mark scheme Mark scheme for question 2(b)(iii)
(c)

Q and R represent isotopes of the same element.

(c)(i)

Explain, in terms of subatomic particles, why Q and R are isotopes.

[2]
Reveal mark scheme Mark scheme for question 2(c)(i)
(c)(ii)

A sample containing the isotopes Q and R has this percentage composition by mass.

Q = 20.6 %
R = 79.4 %

Calculate the relative atomic mass (Ar) of this sample of the element.

Give your answer to one decimal place.

[3]
Reveal mark scheme Mark scheme for question 2(c)(ii)

Chemistry Paper 2 November 2023, Question 1 6 marks

This question is about Group 7, the halogens.

(a)

What is the total number of electrons in one fluorine atom?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(a)
(b)

What is the charge on a bromide ion?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(b)
(c)

Which of these describes the element iodine at room temperature?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(c)
(d)

When a halogen is added to a solution containing halide ions, a displacement reaction may occur.

The table shows whether a reaction occurs.

Halogen addedChloride ion
Bromide ion in solution
in solution
Iodide ion in solution
chlorinereactionreaction
bromineno reactionreaction
iodineno reaction
no reaction

Using information from the table, explain the order of reactivity of the three halogens.

[3]
Reveal mark scheme Mark scheme for question 1(d)

Chemistry Paper 1 June 2023 (R), Question 3 8 marks

(a)

The diagram represents an atom of an element.

Figure for question 3
(a)(i)

What is the particle labelled W?

Question 3, shown as an image
[1]
Reveal mark scheme Mark scheme for question 3(a)(i)
(a)(ii)

An atom of this element contains 13 neutrons.

What is the mass number of this element?

Question 3, shown as an image
[1]
Reveal mark scheme Mark scheme for question 3(a)(ii)
(a)(iii)

State why atoms have no overall charge.

[1]
Reveal mark scheme Mark scheme for question 3(a)(iii)
(a)(iv)

What is the charge on the ion usually formed from this element?

Question 3, shown as an image
[1]
Reveal mark scheme Mark scheme for question 3(a)(iv)
(b)

There are two isotopes of the element lithium.

Question 3, shown as an image
(b)(i)

State why both isotopes react in the same way.

[1]
Reveal mark scheme Mark scheme for question 3(b)(i)
(b)(ii)

A sample of lithium contains 7.60%36Li and 92.4%73Li

Calculate the relative atomic mass, Ar, of this sample of lithium.

Give your answer to two decimal places.

[3]
Reveal mark scheme Mark scheme for question 3(b)(ii)

Chemistry Paper 1 June 2023, Question 7 14 marks

This question is about the three halogens, bromine, chlorine and iodine.

(a)

Give the number of protons and the number of neutrons in an atom of iodine–127

number of protons

number of neutrons

[2]
Reveal mark scheme Mark scheme for question 7(a)
(b)

A sample of bromine contains two isotopes.

• Br–79 with relative abundance 52.8 %

• Br–81 with relative abundance 47.2 %

Calculate the relative atomic mass (Ar) of this sample of bromine.

Give your answer to three significant figures.

[3]
Reveal mark scheme Mark scheme for question 7(b)
(c)

Aluminium reacts with chlorine to form aluminium chloride.

This is the equation for the reaction.

Question 7, shown as an image

Calculate the minimum mass of chlorine needed to form 26.7 g of aluminium chloride.

[for Cl2, Mr = 71 for AlCl3, Mr = 133.5]

[3]
Reveal mark scheme Mark scheme for question 7(c)
(d)

A student mixes the following pairs of solutions.

Pair 1 bromine solution and potassium chloride solution

Pair 2 bromine solution and potassium iodide solution

Explain how the student can use the results of these experiments to show the order of reactivity of the three halogens, bromine, chlorine and iodine.

Include observations in your answer.

[6]
Reveal mark scheme Mark scheme for question 7(d)

Chemistry Paper 2 June 2023 (R), Question 1 6 marks

(a)

The table lists three subatomic particles.

Complete the table by giving the missing information.

Figure for question 1
[2]
Reveal mark scheme Mark scheme for question 1(a)
(b)
Figure for question 1
(b)(i)

How are elements arranged in the Periodic Table?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(b)(i)
(b)(ii)

Which statement is correct about the position of phosphorus, P, in the Periodic Table?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(b)(ii)
(b)(iii)

Explain which of the four elements in the diagram is least reactive.

[2]
Reveal mark scheme Mark scheme for question 1(b)(iii)

Chemistry Paper 2 January 2023, Question 1 7 marks

(a)

The diagram shows the electronic configuration of an atom of an element.

Figure for question 1

Complete the table by giving the missing information.

Figure for question 1
[3]
Reveal mark scheme Mark scheme for question 1(a)
(b)

The table gives information about four different species, W, X, Y and Z.

SpeciesNumber of protonsNumber of neutronsNumber of electrons
W222
X131410
Y171817
Z172017
(b)(i)

Give the mass number of W.

[1]
Reveal mark scheme Mark scheme for question 1(b)(i)
(b)(ii)

Give a reason why X has a 3+ charge.

[1]
Reveal mark scheme Mark scheme for question 1(b)(ii)
(b)(iii)

Explain why Y and Z are isotopes of the same element.

[2]
Reveal mark scheme Mark scheme for question 1(b)(iii)

Chemistry Paper 1 June 2022, Question 1 5 marks

The diagram shows the electronic configuration of an atom of an element.

Figure for question 1
(a)

Name the part of the atom that contains the protons and neutrons.

[1]
Reveal mark scheme Mark scheme for question 1(a)
(b)

Give the number of protons in this atom.

[1]
Reveal mark scheme Mark scheme for question 1(b)
(c)

Give the number of the group that contains this element.

[1]
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(d)

Give the number of the period that contains this element.

[1]
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(e)

Give the charge on the ion formed from this atom.

[1]
Reveal mark scheme Mark scheme for question 1(e)

Chemistry Paper 1 June 2022 (R), Question 1 6 marks

(a)

The diagram represents an atom of an element.

Figure for question 1

Use numbers from the box to complete the table.

You may use each number once, more than once or not at all.

Figure for question 1
[4]
Reveal mark scheme Mark scheme for question 1(a)
(b)

In terms of sub‑atomic particles, state a similarity and a difference for isotopes of the same element.

similarity

difference

[2]
Reveal mark scheme Mark scheme for question 1(b)

Chemistry Paper 2 June 2022 (R), Question 1 5 marks

The diagram shows the sub‑atomic particles in an atom of an element.

Figure for question 1
(a)(i)

Give the name of each of the sub‑atomic particles labelled P, Q and R.

[3]
Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)

Give the name of the part of the atom labelled S.

[1]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(b)

Give the name of this element.

[1]
Reveal mark scheme Mark scheme for question 1(b)

Chemistry Paper 1 January 2022, Question 5 11 marks

Also involves Amounts of substance in equations · Limiting reactants

(a)

Complete the table to show the relative mass and relative charge of a proton and a neutron.

Figure for question 5
[2]
(b)

Magnesium has three isotopes.

(b)(i)

State the meaning of the term isotopes.

[2]
Reveal mark scheme Mark scheme for question 5(b)(i)
(b)(ii)

The symbol for an atom of one isotope of magnesium is

Question 5, shown as an image

Give the number of protons, neutrons and electrons in one atom of this isotope.

number of protons

number of neutrons

number of electrons

[2]
Reveal mark scheme Mark scheme for question 5(b)(ii)
(b)(iii)

A sample of magnesium contains these percentages of the three isotopes.

Mg‑24 = 79.00 % Mg‑25 = 10.00 % Mg‑26 = 11.00 %

Use this information to show that the relative atomic mass of magnesium is 24.32

[2]
Reveal mark scheme Mark scheme for question 5(b)(iii)
(b)(iv)

One mole of magnesium has a mass of 24.32 g. There are 6.022 × 1023 atoms in one mole.

Calculate the mass, in grams, of one atom of magnesium.

Give your answer to 4 significant figures.

[2]
Reveal mark scheme Mark scheme for question 5(b)(iv)
(c)

The equation for the reaction between magnesium and oxygen is

Question 5, shown as an image

Determine the maximum amount, in moles, of magnesium oxide that can be produced from 0.50 mol of magnesium and 0.20 mol of oxygen.

[1]
Reveal mark scheme Mark scheme for question 5(c)

Chemistry Paper 2 January 2021, Question 1 5 marks

The diagram shows an atom of an element.

Figure for question 1
(a)(i)

What is the name of the particle labelled Y?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)

Give the mass number of this atom.

[1]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(a)(iii)

Name this element.

Use the Periodic Table on page 2 to help you.

[1]
Reveal mark scheme Mark scheme for question 1(a)(iii)
(b)

There are two isotopes of this element.

Give one way, in terms of sub-atomic particles, that these isotopes are the same and one way that they are different.

[2]

Chemistry Paper 2 November 2020 (R), Question 2 7 marks

Thallium, Tl, is an element in Group 3 and Period 6 of the Periodic Table.

The atomic number of thallium is 81

(a)

How many electrons are there in the outer shell of an atom of thallium?

Question 2, shown as an image
[1]
Reveal mark scheme Mark scheme for question 2(a)
(b)

A thallium ion has a charge of 3+

How many electrons are there in this thallium ion?

Question 2, shown as an image
[1]
Reveal mark scheme Mark scheme for question 2(b)
(c)

A sample of thallium contains two isotopes.

The table shows the mass number and percentage abundance of each isotope in the sample.

IsotopeMass numberPercentage abundance (%)
thallium-20320330.80
thallium-20520569.20
(c)(i)

Give the number of protons and the number of neutrons in one atom of the thallium-205 isotope.

number of protons........

number of neutrons........

[2]
Reveal mark scheme Mark scheme for question 2(c)(i)
(c)(ii)

Calculate the relative atomic mass of this sample of thallium.

Give your answer to one decimal place.

[3]
Reveal mark scheme Mark scheme for question 2(c)(ii)

Chemistry Paper 1 January 2020 (R), Question 1 6 marks

The diagram shows the particles in the atom of an element.

Figure for question 1
(a)

Particle Y is a proton.

What is particle Z?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(a)
(b)

Which of these has the smallest mass?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(b)
(c)

What is the mass number of this atom?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(c)
(d)

What is the atomic number of this atom?

Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(d)
(e)(i)

Identify the element that contains this atom.

[1]
(e)(ii)

State what is formed when this atom loses its outer shell electrons.

[1]
Reveal mark scheme Mark scheme for question 1(e)(ii)

Chemistry Paper 1 January 2020, Question 2 8 marks

The diagram shows the electronic configuration of an atom of an element.

Figure for question 2
(a)

Complete the table by giving the missing information about this atom.

Figure for question 2
[5]
Reveal mark scheme Mark scheme for question 2(a)
(b)

This element has three isotopes.

The table shows the mass number and percentage abundance of each isotope in a sample of this element.

Mass numberPercentage abundance (%)
2479.2
2510.0
2610.8

Calculate the relative atomic mass (Ar) of this element.

Give your answer to one decimal place.

[3]
Reveal mark scheme Mark scheme for question 2(b)

Chemistry Paper 2 June 2019, Question 1 6 marks

The diagram shows the particles in an atom of an element.

Figure for question 1
(a)

The box gives the names of some particles.

Figure for question 1

Use words from the box to label the diagram.

[3]
Reveal mark scheme Mark scheme for question 1(a)
(b)

Give the mass number of this atom.

[1]
Reveal mark scheme Mark scheme for question 1(b)
(c)

Complete the sentence about isotopes.

Isotopes are atoms that have the same number of........

but have a different number of........ .

[2]
Reveal mark scheme Mark scheme for question 1(c)

Chemistry Paper 2 June 2019 (R), Question 2 7 marks

The diagram represents an atom of boron.

Figure for question 2
(a)

Use information from the diagram to complete the table.

The first row has been done for you.

Figure for question 2
[5]
Reveal mark scheme Mark scheme for question 2(a)
(b)

Boron has two isotopes, boron‑10 and boron‑11.

A sample of boron contains 18.7% of boron‑10 and 81.3% of boron‑11.

Calculate the relative atomic mass of this sample of boron.

[2]
Reveal mark scheme Mark scheme for question 2(b)

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