Isotopes
2.3What the syllabus asks of you
- Define isotopes as different atoms of the same element that have the same number of protons but different numbers of neutrons
- State that isotopes of the same element have the same chemical properties because they have the same number of electrons and therefore the same electronic configuration
- Interpret and use symbols for atoms, e.g. 12 6C, and ions, e.g. 35 17Cl –
- Calculate the relative atomic mass of an element from the relative masses and abundances of its isotopes
Read the notes first
Chapter 2: Isotopes
Drill this topic
Every question on Isotopes, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
23 questions
1May / June 2026 · Paper 11 · Q3Show mark scheme →
A1 electrons, 2 isomers
B1 electrons, 2 isotopes
C1 neutrons, 2 isomers
D1 neutrons, 2 isotopes
Mark scheme
2May / June 2026 · Paper 12 · Q3Show mark scheme →
Athe number of outer-shell electrons in each atom
Bthe total number of electrons in each atom
Cthe number of neutrons in each atom
Dthe number of protons in each atom
Mark scheme
3May / June 2025 · Paper 11 · Q4Show mark scheme →
Aatoms of different elements that have the same number of electrons
Batoms of different elements that have the same number of neutrons
Catoms of the same element that have different numbers of electrons
Datoms of the same element that have different numbers of neutrons
Mark scheme
4May / June 2025 · Paper 11 · Q5Show mark scheme →
A51
B52
C53
D54
Mark scheme
5May / June 2025 · Paper 12 · Q6Show mark scheme →
A151.88
B151.96
C152.00
D152.04
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6Oct / Nov 2024 · Paper 11 · Q5Show mark scheme →
AThe chemical properties of both ions are the same.
BThe number of electrons in each ion is different.
CThe number of neutrons in each ion is the same.
DThe number of protons in each ion is different.
Mark scheme
7Oct / Nov 2024 · Paper 11 · Q8Show mark scheme →
A1, 2 and 3
B1 and 3 only
C2 and 3 only
D3 only
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8Oct / Nov 2024 · Paper 12 · Q4Show mark scheme →
A21.0
B21.2
C21.5
D21.7
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9May / June 2024 · Paper 11 · Q4Show mark scheme →
AW and X
BW and Z
CX and Z
DY and Z
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10May / June 2024 · Paper 12 · Q4Show mark scheme →
Ax+0.5
Bx+1.0
Cx+1.5
Dx+2.0
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11Oct / Nov 2023 · Paper 11 · Q4Show mark scheme →
AX and Y are the same element.
BX and Z are the same element.
CX has more protons than Y.
DZ has more neutrons than Y.
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12Oct / Nov 2023 · Paper 12 · Q4Show mark scheme →
AThey are atoms with the same number of electrons and a different number of protons.
BThey are atoms with the same number of neutrons and the same number of electrons.
CThey are atoms with the same number of protons and the same chemical properties.
DThey are atoms with the same number of protons and the same physical properties.
Mark scheme
13May / June 2023 · Paper 11 · Q3Show mark scheme →
A1 and 2 only
B1 and 3 only
C1 and 4
D1, 2 and 3
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14May / June 2023 · Paper 12 · Q3Show mark scheme →
ABromine contains the two isotopes in equal proportions.
BBromine has different oxidation states.
CBromine isotopes have different numbers of protons.
DBromine is radioactive.
Mark scheme
15Oct / Nov 2022 · Paper 11 · Q7Show mark scheme →
A25, 75
B40, 60
C50, 50
D75, 25
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16May / June 2022 · Paper 12 · Q6Show mark scheme →
A1, 2 and 3
B1 and 2 only
C1 and 3 only
D2 and 4
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17May / June 2022 · Paper 12 · Q7Also set in May / June 2022 Paper 11Show mark scheme →
A2
B3
C4
D5
Mark scheme
18May / June 2021 · Paper 12 · Q8Show mark scheme →
A1 and 2
B1 and 3
C1 only
D2 and 3
Mark scheme
19May / June 2020 · Paper 11 · Q7Show mark scheme →
Aatoms of different elements which have the same number of electrons
Batoms of different elements which have the same number of neutrons
Catoms of the same element which have different numbers of electrons
Datoms of the same element which have different numbers of neutrons
Mark scheme
20Oct / Nov 2019 · Paper 12 · Q3Show mark scheme →
Aelectrons, isomers
Belectrons, isotopes
Cneutrons, isomers
Dneutrons, isotopes
Mark scheme
21Oct / Nov 2017 · Paper 11 · Q6Show mark scheme →
A$^{34}_{16}\text{S}^{2+}$
B$^{34}_{16}\text{S}$
C$^{34}_{16}\text{S}^{2-}$
D$^{36}_{16}\text{S}$
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22May / June 2016 · Paper 11 · Q13Show mark scheme →
A2
B3
C4
D5
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23May / June 2016 · Paper 12 · Q4Show mark scheme →
Aelectrons and a different number of protons.
Bneutrons and the same number of electrons.
Cprotons and the same chemical properties.
Dprotons and the same physical properties.
Mark scheme