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Edexcel GCSE Chemistry

Topic questions Atomic structure and the periodic table Isotopes & relative atomic mass

Isotopes & relative atomic mass

8 questions · 75 marks · about 1.5 hours

Isotopes and relative atomic mass questions

Edexcel 1CH0 Isotopes and relative atomic mass 8 questions

Paper 1 June 2025 Higher tier, Question 2 9 marks

(a)

Atoms of neon are made up of subatomic particles.

(a)(i)

Figure 2 shows some information about the subatomic particles in neon atoms.

Complete Figure 2 with the missing information.

Figure for question 2
[3]
Reveal mark scheme Mark scheme for question 2(a)(i)
(a)(ii)

All atoms of neon have an atomic number of 10.

Describe what information about the number of subatomic particles can be obtained from the atomic number of neon.

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

Explain why atoms of neon are electrically neutral.

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

A sample of neon contains three isotopes

90.48% of neon-20

0.27% of neon-21

9.25% of neon-22

Using this information, calculate the relative atomic mass of this sample of neon.

relative atomic mass =........

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

Paper 2 June 2023 Higher tier, Question 3 9 marks

Figure 6 shows some information about the group 1 metals.

Figure for question 3
(a)

Explain, in terms of their electronic configurations, why these metals are placed in group 1 of the periodic table.

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

Which row shows two correct properties of group 1 metals?

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

The word equation for the reaction of potassium with bromine is

potassium + bromine maths symbol potassium bromide

Add the missing state symbol and balance the equation for this reaction.

Question 3, shown as an image
[2]
Reveal mark scheme Mark scheme for question 3(c)
(d)

A sample of potassium contains three isotopes, potassium-39, potassium-40 and potassium-41.

(d)(i)

Explain the meaning of the term isotopes.

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

This sample of potassium contains

93.25% potassium-39

0.02% potassium-40

6.73% potassium-41

Calculate the relative atomic mass of this sample of potassium.

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

Paper 1 November 2021 Higher tier, Question 9 11 marks

(a)

An ion of element X can be represented as

Question 9, shown as an image

This ion of element X has 54 electrons.

Calculate the number of protons and the number of neutrons in this ion.

Question 9, shown as an image
[2]
Reveal mark scheme Mark scheme for question 9(a)
(b)

A sample of silicon contains isotopes.

(b)(i)

State, in terms of subatomic particles, how atoms of these isotopes are the same.

[1]
Reveal mark scheme Mark scheme for question 9(b)(i)
(b)(ii)

This sample of silicon contains three isotopes.

92% of the atoms are silicon-28 5% of the atoms are silicon-29 3% of the atoms are silicon-30

Calculate the relative atomic mass of silicon in this sample.

relative atomic mass =........

[2]
Reveal mark scheme Mark scheme for question 9(b)(ii)
(c)

*(c) Figure 6 shows some properties of three substances, A, B and C.

Figure for question 9

Deduce, using the information in Figure 6, the structure and bonding of substances A, B and C, explaining their properties in terms of their structure and bonding.

[6]
Reveal mark scheme Mark scheme for question 9(c)

Paper 1 November 2020 Foundation tier, Question 2 8 marks

Chlorine has an atomic number of 17.

(a)

Figure 3 shows the arrangement of electrons in an atom of chlorine.

Figure for question 2
(a)(i)

What is the electronic configuration of this atom?

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

Explain, using Figure 3, why chlorine belongs to group 7 of the periodic table.

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

The nucleus of an atom is made up of protons and neutrons. Atoms of chlorine contain 17 protons.

Figure 4 shows some information about a proton, a neutron and an electron.

relative massrelative charge
proton1+1
neutron10
electronvery small−1
Question 2, shown as an image
(b)(i)

Explain, using the information in Figure 3 and Figure 4, why atoms of chlorine have no overall charge.

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

Atoms of chlorine-37 have a mass number of 37.

Calculate the number of neutrons in atoms of chlorine-37.

number of neutrons =........

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

There are two isotopes of chlorine, chlorine-35 and chlorine-37.

Explain the meaning of the term isotopes.

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

Paper 1 November 2020 Higher tier, Question 6 11 marks

Titanium and iron are examples of transition metals.

(a)

Figure 6 shows the percentage abundance of each isotope in a sample of titanium.

Figure for question 6

Calculate the relative atomic mass of titanium in this sample.

[3]
Reveal mark scheme Mark scheme for question 6(a)
(b)

Iron, when heated in air, reacts with oxygen to form iron oxide.

(b)(i)

This reaction is an example of

Question 6, shown as an image
[1]
Reveal mark scheme Mark scheme for question 6(b)(i)
(b)(ii)

The equipment shown in Figure 7 can be used to find the mass of oxygen that combines with iron.

Figure for question 6

Describe how the equipment shown in Figure 7 could be used to find the mass of oxygen that combines with 0.500 g of iron wool in a crucible and lid of known mass.

[3]
Reveal mark scheme Mark scheme for question 6(b)(ii)
(c)

2.24 g of iron combines with 0.96 g of oxygen to form an oxide of iron.

Determine the formula of this oxide of iron and use it to complete the balanced equation.

(relative atomic masses: Fe = 56.0, O = 16.0)

You must show your working.

balanced equation for the reaction is

Question 6, shown as an image
[4]
Reveal mark scheme Mark scheme for question 6(c)

Paper 1 June 2019 Higher tier, Question 2 10 marks

Figure for question 2
(a)

Using the letters A, E, G, J, X and Z

(a)(i)

give the letters of the two elements that are non-metals

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

give the letters of two elements in period 2

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

give the letter of an element that normally forms an ion with a charge of +1.

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

Element E has an atomic number of 5. In a sample of E there are two isotopes. One isotope has a mass number of 10 and the other isotope has a mass number of 11.

(b)(i)

Explain, in terms of subatomic particles, what is meant by the term isotopes.

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

All atoms of element E in this sample contain

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

Element X has an atomic number of 18.

State the electronic configuration of an atom of element X.

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

In an experiment, 3.5 g of element A reacted with 4.0 g of element G to form a compound.

Calculate the empirical formula of this compound. (relative atomic masses: A = 7, G = 16)

You must show your working.

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

Paper 2 June 2019 Higher tier, Question 6 10 marks

Some of the elements in the periodic table are metals.

(a)

The electronic configuration of a metal is 2.8.3

Which row shows the group and period of the periodic table where this metal is found?

Figure for question 6
[1]
Reveal mark scheme Mark scheme for question 6(a)
(b)

Lithium, potassium and rubidium are alkali metals.

(b)(i)

Describe what you would see when a small piece of rubidium is dropped on to water.

[2]
Reveal mark scheme Mark scheme for question 6(b)(i)
(b)(ii)

The electronic configuration of lithium is 2.1 The electronic configuration of potassium is 2.8.8.1 Lithium is less reactive than potassium.

Explain, in terms of their electronic configurations, why lithium is less reactive than potassium.

[3]
Reveal mark scheme Mark scheme for question 6(b)(ii)
(c)

Lithium has two naturally occurring isotopes, lithium‑6 and lithium‑7.

A sample of lithium contains 7.59 % of lithium‑6 92.41% of lithium‑7.

Calculate the relative atomic mass of lithium in this sample.

Give your answer to two decimal places. You must show your working.

[4]
Reveal mark scheme Mark scheme for question 6(c)

Paper 1 June 2018 Foundation tier, Question 3 7 marks

(a) Atoms contain electrons, neutrons and protons.

(a)
(a)(i)

Draw one line to link each particle to its correct relative charge.

Figure for question 3
[2]
Reveal mark scheme Mark scheme for question 3(a)(i)
(a)(ii)

Which of the following is the relative mass of a proton?

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

Argon is in group 0 of the periodic table.

Identify, using the periodic table on the back cover of this paper, which of these elements is in the same period as argon.

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

Figure 4 shows the atomic number and mass number of two isotopes of argon.

isotopeatomic numbermass number
argon-381838
argon-401840
Question 3, shown as an image

Describe the structure of an atom of argon-38 and of an atom of argon-40.

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

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