Please check the examination details below before entering your candidate information
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel Level 3 GCE
Tuesday 2 June 2026
Mark Scheme
Morning (Time: 1 hour 45 minutes) Paper
9CH0/01
(Results)
reference
Chemistry
Advanced
PAPER 1: Advanced Inorganic and Physical Chemistry
You must have: Total Marks
Summer 2026
Scientific calculator, Data Booklet, ruler
Instructions
• Use black ink or ball‑point pen. Pearson Edexcel GCE In Chemistry (9CH0)
• IfFillpencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• centre number
in the boxes at the top of this page with your name,
and candidate number.
Paper 01 Advanced Inorganic and Physical Chemistry
• Answer all questions.
• Answer the questions in the spaces provided
– there may be more space than you need.
9CH0_01
Information
• The total mark for this paper is 90.
• The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• toForstructure
the question marked with an asterisk (*), marks will be awarded for your ability
your answer logically, showing the points that you make are related or
follow on from each other where appropriate.
• A Periodic Table is printed on the back cover of this paper.
Advice
• Read each question carefully before you start to answer it.
• Show all your working in calculations and include units where appropriate.
• Check your answers if you have time at the end. Turn over
P74453APearson Education Ltd.
P:1/1/1/1/1/1/1/1/1/1/
*P74453A0128*
, Answer ALL questions.
Edexcel and BTEC Qualifications
Some questions must be answered with a cross in a box . If you change your mind about an
answer, put a line through the box and then mark your new answer with a cross .
1 This question is about ionisation energy. Edexcel and BTEC qualifications are awarded by Pearson, the UK’s
The graph shows the first ionisation energies of 13 successive elements in the largest awarding body. We provide a wide range of qualifications
Periodic Table in order of increasing atomic number. including academic, vocational, occupational and specific
programmes for employers. For further information visit our
Trends in first ionisation energies can be used to identify the group to which an
element belongs. qualifications websites at or .
Alternatively, you can get in touch with us using the details on our
The letters are not the symbols for the elements. contact us page at
C
+
+
B L
+
+
Ionisation A + Pearson: helping people progress, everywhere
energy H K
+ +
/ kJ mol–1 E + J Pearson aspires to be the world’s leading learning company. Our aim is to help
+ G
+ N everyone progress in their lives through education. We believe in every kind of
+ F +
D + learning, for all kinds of people, wherever they are in the world. We’ve been
M
involved in education for over 150 years, and by working across 70 countries, in
100 languages, we have built an international reputation for our commitment to
Atomic number
high standards and raising achievement through innovation in education. Find
out more about how we can help you and your students at:
(a) (i) Which statement best describes the first ionisation energy of an element?
(1)
A the energy released on removing 1 mol of electrons
from 1 mol of atoms in the gaseous state
B the energy required to form 1 mol of singly charged positive ions
from 1 mol of atoms
C the energy released when 1 mol of gaseous atoms
forms 1 mol of gaseous singly charged positive ions
D the energy required to remove 1 mol of electrons Summer 2026
from 1 mol of gaseous atoms Question Paper Log Number P74453A
Publication Code 9CH0_01_2606_MS
All the material in this publication is
Pearson
2
*P74453A0228*
, (ii) Explain why a general increase is shown in the graph for the first
ionisation energies of the elements F to L. General Marking Guidance
(2)
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
• Mark schemes should be applied positively. Candidates must be rewarded
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . for what they have shown they can do rather than penalised for omissions.
• Examiners should mark according to the mark scheme not according to their
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
perception of where the grade boundaries may lie.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
• There is no ceiling on achievement. All marks on the mark scheme should be
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
used appropriately.
• All the marks on the mark scheme are designed to be awarded. Examiners
(iii) Identify the reason why the first ionisation energy of element J is lower than should always award full marks if deserved, i.e. if the answer matches the
for element H. mark scheme. Examiners should also be prepared to award zero marks if the
(1)
A the electron is removed from a new shell candidate’s response is not worthy of credit according to the mark scheme.
• Where some judgement is required, mark schemes will provide the principles
B the electron is removed from a new sub-shell
by which marks will be awarded and exemplification may be limited.
C the electron is removed from a fully occupied orbital
• When examiners are in doubt regarding the application of the mark scheme
D the electron is removed from a partially occupied orbital to a candidate’s response, the team leader must be consulted.
• Crossed out work should be marked UNLESS the candidate has replaced it
(b) (i) Which pair of elements belong in Group 2? with an alternative response.
(1)
A elements B and K
B elements C and L
C elements D and M
D elements E and N
(ii) Justify your answer in terms of ionisation energy.
(1)
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
*P74453A0328* Turn over
, Using the Mark Scheme
Deduce the identity of element A. Examiners should look for qualities to reward rather than faults to penalise. This does NOT mean giving credit for incorrect or
inadequate answers, but it does mean allowing candidates to be rewarded for answers showing correct application of principles
Justify your answer, using the graph of first ionisation energies. and knowledge. Examiners should therefore read carefully and consider every response: even if it is not what is expected it may
(3) be worthy of credit.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The mark scheme gives examiners:
• an idea of the types of response expected
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • how individual marks are to be awarded
• the total mark for each question
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • examples of responses that should NOT receive credit.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . / means that the responses are alternatives and either answer should receive full credit.
( ) means that a phrase/word is not essential for the award of the mark, but helps the examiner to get the sense of the expected
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . answer.
Phrases/words in bold indicate that the meaning of the phrase or the actual word is essential to the answer.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ecf/TE/cq (error carried forward) means that a wrong answer given in an earlier part of a question is used correctly in answer to a
later part of the same question.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Candidates must make their meaning clear to the examiner to gain the mark. Make sure that the answer makes sense. Do not give
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . credit for correct words/phrases which are put together in a meaningless manner. Answers must be in the correct context.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quality of Written Communication
Questions which involve the writing of continuous prose will expect candidates to:
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • write legibly, with accurate use of spelling, grammar and punctuation in order to make the meaning clear
• select and use a form and style of writing appropriate to purpose and to complex subject matter
(Total for Question 1 = 9 marks) • organise information clearly and coherently, using specialist vocabulary when appropriate.
Full marks will be awarded if the candidate has demonstrated the above abilities.
Questions where QWC is likely to be particularly important are indicated (QWC) in the mark scheme, but this does not preclude
others.
4
*P74453A0428*
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel Level 3 GCE
Tuesday 2 June 2026
Mark Scheme
Morning (Time: 1 hour 45 minutes) Paper
9CH0/01
(Results)
reference
Chemistry
Advanced
PAPER 1: Advanced Inorganic and Physical Chemistry
You must have: Total Marks
Summer 2026
Scientific calculator, Data Booklet, ruler
Instructions
• Use black ink or ball‑point pen. Pearson Edexcel GCE In Chemistry (9CH0)
• IfFillpencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• centre number
in the boxes at the top of this page with your name,
and candidate number.
Paper 01 Advanced Inorganic and Physical Chemistry
• Answer all questions.
• Answer the questions in the spaces provided
– there may be more space than you need.
9CH0_01
Information
• The total mark for this paper is 90.
• The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• toForstructure
the question marked with an asterisk (*), marks will be awarded for your ability
your answer logically, showing the points that you make are related or
follow on from each other where appropriate.
• A Periodic Table is printed on the back cover of this paper.
Advice
• Read each question carefully before you start to answer it.
• Show all your working in calculations and include units where appropriate.
• Check your answers if you have time at the end. Turn over
P74453APearson Education Ltd.
P:1/1/1/1/1/1/1/1/1/1/
*P74453A0128*
, Answer ALL questions.
Edexcel and BTEC Qualifications
Some questions must be answered with a cross in a box . If you change your mind about an
answer, put a line through the box and then mark your new answer with a cross .
1 This question is about ionisation energy. Edexcel and BTEC qualifications are awarded by Pearson, the UK’s
The graph shows the first ionisation energies of 13 successive elements in the largest awarding body. We provide a wide range of qualifications
Periodic Table in order of increasing atomic number. including academic, vocational, occupational and specific
programmes for employers. For further information visit our
Trends in first ionisation energies can be used to identify the group to which an
element belongs. qualifications websites at or .
Alternatively, you can get in touch with us using the details on our
The letters are not the symbols for the elements. contact us page at
C
+
+
B L
+
+
Ionisation A + Pearson: helping people progress, everywhere
energy H K
+ +
/ kJ mol–1 E + J Pearson aspires to be the world’s leading learning company. Our aim is to help
+ G
+ N everyone progress in their lives through education. We believe in every kind of
+ F +
D + learning, for all kinds of people, wherever they are in the world. We’ve been
M
involved in education for over 150 years, and by working across 70 countries, in
100 languages, we have built an international reputation for our commitment to
Atomic number
high standards and raising achievement through innovation in education. Find
out more about how we can help you and your students at:
(a) (i) Which statement best describes the first ionisation energy of an element?
(1)
A the energy released on removing 1 mol of electrons
from 1 mol of atoms in the gaseous state
B the energy required to form 1 mol of singly charged positive ions
from 1 mol of atoms
C the energy released when 1 mol of gaseous atoms
forms 1 mol of gaseous singly charged positive ions
D the energy required to remove 1 mol of electrons Summer 2026
from 1 mol of gaseous atoms Question Paper Log Number P74453A
Publication Code 9CH0_01_2606_MS
All the material in this publication is
Pearson
2
*P74453A0228*
, (ii) Explain why a general increase is shown in the graph for the first
ionisation energies of the elements F to L. General Marking Guidance
(2)
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
• Mark schemes should be applied positively. Candidates must be rewarded
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . for what they have shown they can do rather than penalised for omissions.
• Examiners should mark according to the mark scheme not according to their
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
perception of where the grade boundaries may lie.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
• There is no ceiling on achievement. All marks on the mark scheme should be
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
used appropriately.
• All the marks on the mark scheme are designed to be awarded. Examiners
(iii) Identify the reason why the first ionisation energy of element J is lower than should always award full marks if deserved, i.e. if the answer matches the
for element H. mark scheme. Examiners should also be prepared to award zero marks if the
(1)
A the electron is removed from a new shell candidate’s response is not worthy of credit according to the mark scheme.
• Where some judgement is required, mark schemes will provide the principles
B the electron is removed from a new sub-shell
by which marks will be awarded and exemplification may be limited.
C the electron is removed from a fully occupied orbital
• When examiners are in doubt regarding the application of the mark scheme
D the electron is removed from a partially occupied orbital to a candidate’s response, the team leader must be consulted.
• Crossed out work should be marked UNLESS the candidate has replaced it
(b) (i) Which pair of elements belong in Group 2? with an alternative response.
(1)
A elements B and K
B elements C and L
C elements D and M
D elements E and N
(ii) Justify your answer in terms of ionisation energy.
(1)
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
*P74453A0328* Turn over
, Using the Mark Scheme
Deduce the identity of element A. Examiners should look for qualities to reward rather than faults to penalise. This does NOT mean giving credit for incorrect or
inadequate answers, but it does mean allowing candidates to be rewarded for answers showing correct application of principles
Justify your answer, using the graph of first ionisation energies. and knowledge. Examiners should therefore read carefully and consider every response: even if it is not what is expected it may
(3) be worthy of credit.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The mark scheme gives examiners:
• an idea of the types of response expected
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • how individual marks are to be awarded
• the total mark for each question
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • examples of responses that should NOT receive credit.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . / means that the responses are alternatives and either answer should receive full credit.
( ) means that a phrase/word is not essential for the award of the mark, but helps the examiner to get the sense of the expected
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . answer.
Phrases/words in bold indicate that the meaning of the phrase or the actual word is essential to the answer.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ecf/TE/cq (error carried forward) means that a wrong answer given in an earlier part of a question is used correctly in answer to a
later part of the same question.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Candidates must make their meaning clear to the examiner to gain the mark. Make sure that the answer makes sense. Do not give
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . credit for correct words/phrases which are put together in a meaningless manner. Answers must be in the correct context.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quality of Written Communication
Questions which involve the writing of continuous prose will expect candidates to:
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • write legibly, with accurate use of spelling, grammar and punctuation in order to make the meaning clear
• select and use a form and style of writing appropriate to purpose and to complex subject matter
(Total for Question 1 = 9 marks) • organise information clearly and coherently, using specialist vocabulary when appropriate.
Full marks will be awarded if the candidate has demonstrated the above abilities.
Questions where QWC is likely to be particularly important are indicated (QWC) in the mark scheme, but this does not preclude
others.
4
*P74453A0428*
