CIE IGCSE Chemistry (0620) Examiner Report June 2023: Summary

Published

1 May 2025

IGCSE Chemistry report illustration with exam papers, one graded A+, and scientific symbols on a yellow background. A hand marks a paper with a red pen.

Contents

This article summarises key insights from the June 2023 CIE IGCSE Chemistry (0620) examiner reports, with a focus on common student errors, recurring question types, and practical teaching strategies. Drawing on my experience as a CIE IGCSE Chemistry examiner since 2012 and a Chemistry teacher since 2007, I’ve highlighted the themes most relevant to classroom planning and targeted revision. Whether you're supporting Core or Extended tier students, this report offers a clear overview of what to prioritise, and why.

Multiple Choice Paper 11 (Core - 0620/11) and Paper 21 (Extended - 0620/21)

The June 2023 examiner reports for CIE IGCSE Chemistry Papers 1 (Core) and 2 (Extended) highlight several recurring issues in students’ performance on the multiple choice questions. Many difficulties were shared across both tiers, while some were specific to the level of challenge in Paper 21.

Core vs Extended: Shared Challenges and Overlap

Of the 40 questions in each paper:

16 questions were identical or near-identical, testing the exact same diagrams, data tables, or definitions.
7 questions were closely related, assessing the same concepts but with reworded scenarios or extended logic.
17 questions were unique to Paper 11, often focused on foundational knowledge, naming, and recall.
17 questions were unique to Paper 21, typically involving extended interpretation, multi-step calculations, or more abstract applications of core principles.

These figures confirm that the Extended paper draws heavily from Core content. The shared questions most often assessed:

Group trends and comparisons (e.g. chlorine vs bromine properties)
Bonding and structure (e.g. covalent bonding in methane, giant structures such as diamond and graphite)
Electrolysis and reactivity (e.g. copper vs iron extraction)
Tests and practical recall (e.g. hydrated copper(II) sulfate, titration setup)
Organic chemistry basics (e.g. polymerisation, fractional distillation)

Examiners reported similar misconceptions across both tiers in these areas. For example:

In a shared question on Group I metals, many students selected an incorrect trend in melting point or density
In an electrolysis question, students across both papers confused anode and cathode functions

Teaching recommendation: Prioritise high-overlap topics when preparing mixed-tier classes. These crossover questions offer an opportunity to address misconceptions and improve outcomes across both Core and Extended entries.

These common performance patterns underpin six key themes identified by examiners across both tiers. Each theme is summarised below with examples and practical teaching strategies.

Theme 1: Identifying Exceptions in Chemical Properties and Reactions

Examiners noted that many candidates struggled with questions that included the word “not.” This was especially true when selecting exceptions to known trends or definitions. These questions typically focused on physical or chemical properties. For example, the Group I elements or standard reaction types.

In Paper 11 Question 10, many students misread the negative phrasing and selected plausible but incorrect answers.
In Paper 21 Question 5, a similar issue occurred. Examiners suggested that candidates may benefit from adding ticks or crosses next to each statement to help process the logic

Teaching strategies:

Train students to underline or highlight key words like not and except in all practice questions
Provide paired examples: one question written positively and one negatively, using the same topic
Use true/false tables to review group trends or reaction properties, reinforcing correct and incorrect statements side by side.

Theme 2: Practical Chemistry and Test Result Recall

Questions requiring knowledge of tests and observations were a consistent challenge. Candidates often confused flame colours, ion test results, or the changes seen when heating hydrated salts.

In Paper 11 Question 13, students struggled to identify both the hydrated form of copper(II) sulfate and the observation when it is heated.
In Paper 21 Question 40, performance was also weak. Candidates were more familiar with the ammonium ion test using sodium hydroxide but were unsure how to test for carbonate ions.

Teaching strategies:

Build a revision grid of common tests (e.g. flame, gas, ion), including reagent, result, and ion detected.
Use practical demonstrations or video clips to reinforce colour changes and effervescence-based tests.
Develop “Which ion is this?” quizzes using partial results to challenge deeper recall and interpretation.

Theme 3: Misconceptions in Electrolysis and Reactivity Trends

Electrolysis questions revealed confusion with:

Electrode polarity
Identifying products
Understanding metal reactivity.

These topics require both recall and interpretation of redox processes.

In Paper 11 Question 9, few students selected the correct answer. Many confused the anode and cathode or misunderstood the movement of ions.
In Paper 21 Question 26, candidates struggled to compare the reactivity of iron and copper and apply it to predict outcomes.

Teaching strategies:

Use annotated electrode diagrams to model movement of ions and electron transfer.
Practice reactivity ranking using displacement reactions and extraction methods.
Reinforce electrode definitions with simple mnemonics and particle diagrams showing ion migration.

Theme 4: Confusion in Organic Structures and Reaction Types

Several questions tested students' ability to recognise functional groups, interpret displayed formulae, and apply acid-base logic in organic contexts. Many responses showed weak conceptual boundaries.

In Paper 11 Question 32, candidates misidentified the –OH group in alcohols as belonging to a carboxylic acid.
In Paper 21 Question 36, most students failed to remove the H⁺ ion from ethanoic acid. This revealed uncertainty about both dissociation and molecular structure.

Teaching strategies:

Use comparison tables showing alcohols vs carboxylic acids (structure, naming, reactions).
Model H⁺ donation in reactions to reinforce the acid behaviour of carboxylic acids.
Provide structure labelling tasks and molecule-matching exercises. This will help build fluency in functional group identification.

Theme 5: Misunderstanding Periodic Trends in Group I and Group VII

Students found it difficult to correctly apply trends in melting point, density, colour, and reactivity across Group I and Group VII. These questions required students to recall qualitative trends and interpret data tables.

In Paper 11 Question 19, candidates confused trends in melting point and density for Group I metals.
In Paper 21 Question 20, few students gave accurate statements about halogen properties.

Teaching strategies:

Use vertical summary tables for each group, with colour coding for trends in reactivity, state, and appearance.
Create sequencing tasks: “Arrange these elements by increasing melting point” etc.
Reinforce explanations of group trends using electron configuration and particle diagrams.

Theme 6: Applying Multi-Step Chemical Reasoning Under Pressure

Some multiple choice questions required candidates to combine two or more ideas. For example, they had to interpret a structure and apply a reaction rule to arrive at the correct answer. These questions exposed gaps in reasoning and, in many cases, signs of guessing.

In Paper 11 Questions 4, 35, and 36, and Paper 21 Questions 17 and 28, examiners noted inconsistent reasoning.
The distribution of responses suggested that many students were not working through the questions logically.

Teaching strategies:

Model how to eliminate incorrect options by checking each against known facts or processes.
Break complex questions into verbalised steps: “What do I know? What do I need to find?”
Use scaffolded MCQs that ask for reasoning steps before selecting a final answer.

Theory Paper 31 (Core - 0620/31) and Paper 41 (Extended - 0620/41)

The CIE IGCSE Chemistry June 2023 examiner reports for Papers 3 (Core Theory) and 4 (Extended Theory) reveal key patterns in student performance across structured, written-response questions. A few topics, such as isotopes, covalent bonding, and chemical testing, appeared in both tiers. However, most of Paper 41’s content required greater depth, more calculation, and higher structural accuracy.

Core vs Extended: Overlap and Distinctions

A detailed comparison of the June 2023 questions from Paper 31 (Core Theory) and Paper 41 (Extended Theory) reveals limited direct overlap between the two tiers. Of the full set of structured questions:

1 question was identical or near-verbatim, testing the definition of an isotope using the same wording.
3 to 4 questions showed closely related content, including covalent bonding diagrams, electrolysis outcomes, ammonia properties, and carboxylic acid reactions
The majority of questions were unique to each paper, with Paper 41 covering more abstract, quantitative, and higher-order applications

Shared topics, such as bonding, chemical tests, and acid–base behaviour, were usually examined at very different levels of depth. For example:

Both papers asked about ammonia, but Paper 41 extended this to include particle-level explanations and ionic equations.
Dot-and-cross diagrams were used in both tiers, but Paper 41 included more atoms, bonding stages, and interpretation steps

Teaching strategies:

Use overlapping themes (e.g. isotopes, acids, bonding) as anchor points for mixed-ability revision.
Emphasise structure, clarity, and scientific language early on, as these are consistently rewarded at both tiers.
- This is the case even when the question formats differ.

This section identifies six major themes drawn from the examiner feedback. Each is grounded in direct commentary and includes practical teaching strategies to help students succeed in both the Core and Extended papers.

Theme 1: Insecure Recall of Chemical Tests and Observations

Examiners noted widespread gaps in students’ knowledge of standard qualitative tests, particularly for common ions and gases. Core and Extended candidates struggled to recall reagents, observations, or both.

In Paper 31 Question 2(b)(ii), many students failed to describe a test for sodium ions, showing uncertainty over flame tests

Diagram of six Bunsen burners with flames in red, yellow, violet, orange, blue-green, and green, labelled with Li⁺, Na⁺, K⁺, Ca²⁺, Cu²⁺, Ba²⁺.

In Paper 41 Question 40, candidates often recalled the test for ammonium ions using aqueous sodium hydroxide, but struggled to describe the test for carbonate ions.

Teaching strategies:

Create a ‘Test Table’ revision sheet covering all required ion, gas, and flame tests — include reagent, observation, and ion confirmed.
Reinforce through matching activities (e.g. ‘Effervescence’ → ‘carbonate + acid’).
Use quick-recall routines (e.g. 5-question starters) to drill observations and conditions.

Theme 2: Poor Mastery of Definitions and Key Terms

Accurate definitions are a consistent expectation, yet many students either wrote incomplete responses or confused related terms. Examiners emphasised the value of structured, syllabus-specific learning of definitions.

In Paper 31 Question 3(d)(i), the definition of oxidation often missed essential detail about electron loss.
Paper 41 comments included: “More learning and practice of the definitions stated in this syllabus needs to be carried out
One exception was Paper 41 Question 8(c)(iii), where candidates generally gave a strong definition of an alloy

Teaching strategies:

Build a definitions deck (flashcards or digital), focusing on syllabus-specified terms
Encourage students to explain each definition aloud, then refine it to match mark scheme language
Highlight near-miss definitions for peer correction using previous exam examples

Theme 3: Common Errors in Naming and Representing Organic Molecules

Naming organic compounds and drawing correct displayed formulae presented difficulties across both tiers. Examiners commented on issues ranging from mislabelled salts to chemically impossible structures.

Students frequently wrote “sulfide” instead of “sulfate” when naming salts in Paper 31
In Paper 41, displayed formulas were drawn with five bonds around carbon, and some omitted key bonds (e.g. the O–H bond in alcohols)
Functional group identification was often incomplete or confused, particularly with carboxylic acids

Teaching strategies:

Use structure-annotation tasks to reinforce correct bonding and valency.
Provide model answers for common structures (ethanol, ethanoic acid, alkenes), including labelled functional groups
Reinforce the difference between names ending in “-ide”, “-ate”, and their associated ions.

Theme 4: Weak Understanding of Physical Properties and Particle-Level Descriptions

Misconceptions were common when describing particle behaviour, diffusion, or physical states. Many candidates confused physical with chemical properties or used vague phrasing in place of scientific explanation.

In Paper 31 Question 8(a), students described “inertness” as a physical property, a chemical misconception
In 8(c)(iii), some wrote: “molecules spread from a low concentration to a high concentration”, misunderstanding diffusion
Examiners also criticised vague language, urging candidates to avoid non-specific terms like ‘it’ and ‘they’.

Teaching strategies:

Practise rewriting vague answers (“It changes”) into precise particle-based statements (“The particles move further apart)
Compare and contrast physical vs chemical properties using exam-style true/false statements.
Use labelled particle diagrams to support answers on diffusion, state changes, and pressure/temperature effects.

Illustration of increased gas pressure showing more gas molecule collisions with container walls compared to a lower pressure scenario.

Example of a labelled particle diagram to support how pressure affects collisions

Theme 5: Errors in Practical Method Writing and Planning Questions

Candidates often provided general or incomplete answers when asked to describe practical methods or outline experiments. Examiners stressed that students must explain how and why each step is taken, not just list equipment.

In Paper 41 Question 3, some students gave a full list of apparatus but omitted key method steps, such as forming the required solution before crystallisation.
Others failed to explain the purpose of filtering or heating steps or gave stock phrases without application.

Teaching strategies:

Model step-by-step method writing using “Do → Because” structures to build reasoning.
Provide jumbled method steps for students to sequence and explain.
Mark sample answers as a class, using examiner-style annotations to highlight missing justifications.

Theme 6: Structural Misunderstanding in Equation Writing and Ionic Formulae

Formula and equation errors were widespread in both ionic and molecular contexts. Students often misused charges, omitted state symbols, or wrote implausible products.

In Paper 41, candidates commonly gave incorrect ionic charges for lead(II) and sulfate, leading to formulas like Pb₂SO₄ or Pb(SO₄)₂.
In a precipitation equation task, many included incorrect species or failed to balance correctly.

Teaching strategies:

Reinforce ion charges and formula writing through repetitive practice (e.g. ‘Swap and drop’ tasks).
Use colour-coded equations to show spectator vs reacting ions.
Provide mixed-recall activities combining formulae, charges, and equation construction with state symbols.

Practical Test Paper 51 (0620/51)

The June 2023 examiner report for Paper 51 highlights a range of issues in how candidates carried out and interpreted practical tasks. Many students showed strong familiarity with common techniques such as titration and gas testing. However, examiners noted recurring weaknesses in data recording, phrasing of observations, and justifying experimental plans.

Unlike the theory papers, the commentary for Paper 51 does not reference specific question numbers. Instead, the feedback reflects general patterns observed across the full set of practical tasks.

This article outlines five key themes from the examiner feedback, supported by practical teaching strategies to build confidence and exam precision.

Theme 1: Inconsistent Use of Decimal Places in Burette Readings

Accurate and consistent recording of titres continues to be a common source of lost marks. Candidates were often penalised for using the correct number of significant figures instead of decimal places — or for unrealistic readings altogether.

Some students gave readings such as 25 or 50 cm³, which are not realistic titres.
Others added burette readings instead of subtracting them.
A number of candidates used inconsistent decimal places across their recorded values.

Teaching strategies:

Reinforce that burette readings must be recorded to two decimal places, e.g. 23.45 cm³ instead of 23.4 or 23.450.
Practise titration calculations from tables with mixed values and ask students to identify inconsistencies.
Use error-spotting activities with common student answers to reinforce proper subtraction (final – initial reading).

Theme 2: Misunderstood Role of the White Tile in Titrations

Although many candidates recognised that a white tile is used in titration setups, few explained its function precisely.

Burette setup with clamp and stand, conical flask containing blue solution on a white tile, labelled components include burette, clamp, and tile.

Diagram of titration set up with the poorly justified “white tile”

Vague answers were not credited, and some candidates offered incorrect purposes.

Common errors included saying the white tile “allowed the colours to be seen” or “protected the bench”.
Creditworthy responses specified that it makes colour changes clearer.

Teaching strategies:

Emphasise phrasing such as: “The white tile makes it easier to see the colour change clearly.”
Use paired examples of vague vs precise responses in short-answer training.
Show titration setups with and without white tiles to generate discussion on visibility and practical function.

Theme 3: Vague or Incomplete Gas Test Observations

Gas tests require accurate observation and correct terminology. While many candidates carried out tests correctly, others described observations in vague terms or omitted key information.

Candidates lost marks for saying “a white solid formed” without using the word “precipitate”.
In questions about unknown gases, some did not specify which test gave the positive result.

Teaching strategies:

Provide structured recall drills with gas test setups, expected results, and required wording.
Reinforce key terminology: precipitate, squeaky pop, relights glowing splint, etc.
Ask students to write full observations for positive and negative tests in table format.

Theme 4: Planning Tasks – Overuse of Apparatus Lists and Missed Justifications

Many candidates approached method-writing questions by listing equipment or variables instead of focusing on how the method would be carried out. This approach often missed marks.

Examiners noted that candidates frequently listed apparatus without stating what it was used for.
Full credit was awarded only when candidates explained both the sequence and function of each step — for example, stating that the solution is “heated to crystallisation point, then left to cool.”

Teaching strategies:

Practise writing method steps in “Action → Reason” format (e.g. “Filter to remove excess solid”).
Use scaffolded planning prompts that focus on steps rather than equipment names.
Provide mark scheme comparisons showing why one method scores full marks while another method doesn’t.

Theme 5: Naming vs Formula – Contradictions and Accuracy

When asked for a name or formula of a compound, candidates were often credited for either, but not both if one contradicted the other. Misused charges and incorrect ionic formulas led to lost marks.

For example, giving a correct name but writing an incorrect formula (e.g. Pb(SO₄)₂ for lead(II) sulfate) invalidated the response.
Candidates were also penalised for combining ions incorrectly or omitting necessary charges.

Teaching strategies:

Emphasise that students should give either a correct name or correct formula, not both, unless confident.
Build in formula construction tasks that stress charge balancing and ion pairing.
Provide side-by-side examples of correct vs incorrect name-formula pairings and their impact on mark schemes.

Alternative to Practical Paper 61 (0620/61)

The June 2023 examiner report for Paper 61 highlights a number of practical misconceptions and gaps in technique when candidates are asked to describe, interpret, or plan experiments without performing them directly. While some responses showed good theoretical knowledge, common errors in terminology, measurement conventions, and method structure caused many to lose marks.

Unlike the theory papers, the commentary for Paper 61 does not reference specific question numbers. Instead, the feedback reflects general patterns observed across the full set of alternative-to-practical tasks.

This article outlines five key themes from the examiner commentary, each supported by practical, classroom-ready strategies.

Theme 1: Decimal Place Errors in Apparatus Readings

Candidates frequently lost marks when recording values from tables, thermometers, or measuring cylinders due to inconsistent decimal place usage.

For example, some students gave values such as 21 and 21.0 in the same table, which were not considered consistent.
Examiners reminded teachers that significant figures are not the same as decimal places in this context.

Teaching strategies:

Reinforce the rule: readings should match the resolution of the apparatus — e.g. 0.0 °C for thermometers marked to 0.1 °C.
Provide practice tables with mixed decimal formats and ask students to standardise the data.
Use error-spotting tasks focused on readings from burettes, thermometers, and balances.

Theme 2: Misuse of the Term ‘Observation’ in Gas Tests

Many students incorrectly described a gas being “given off” or “produced” as an observation, rather than describing what they would actually see in the gas test.

For example, “gas released” does not score — examiners expected terms like “effervescence”, “fizzing”, or “bubbles of gas”.
The distinction between observation and conclusion was often misunderstood.

Teaching strategies:

Use side-by-side examples showing acceptable observations vs unacceptable conclusions.
Create a matching activity: stimulus → observation → conclusion, to reinforce the hierarchy.
Emphasise in lessons that “observations” = things seen, heard, or measured.

Theme 3: Incomplete or Incorrect Use of ‘Precipitate’ Terminology

Students often described mixtures as “cloudy” or “milky” without using the term precipitate, which was required for full credit.

Examiners noted that ‘precipitate’ should be used whenever a solid forms from the reaction between two solutions.
Descriptions such as “the solution changed colour and became cloudy” were not sufficient.

Teaching strategies:

Use visual examples of precipitates to build familiarity and link observation to terminology.
Train students to write: “[Colour] precipitate formed” as a standard response.
Rehearse the difference between colour changes in solution vs precipitate formation.

Theme 4: Planning Tasks – Omitted Quantities, Tools, or Justifications

Candidates struggled to write complete practical methods. Many responses missed specific volumes or masses, failed to name appropriate containers, or gave vague descriptions of variables.

Common issues:
- Stating “amount of liquid” rather than volume
- Using “amount of solid” rather than mass
- Referring to “how fast” a substance dissolves, even when the question asked about how much

Teaching strategies:

Use scaffolded method templates: What? How much? How is it measured? Why?
Highlight vague phrases in peer responses and replace them with measurable terms.
Include comparative tasks: “This response scores 2/5 — what’s missing?”

Theme 5: Diagrams and Apparatus Labels Missing Key Components

While many students correctly named apparatus such as filtration or heating equipment, diagrams were often incomplete or poorly labelled.

Examiners noted that diagrams of filtration often omitted the funnel or filter paper.

Diagram showing filtration process with a mixture poured through a filter funnel and paper, separating residue at the top and filtrate collecting below.

Example diagram for filtration with all equipment correct labelled

In preparation methods, candidates skipped steps like heating to dissolve or drying crystals.
Marks were lost for failing to state what each piece of apparatus was used for.

Teaching strategies:

Provide partially labelled diagrams and ask students to complete them with missing equipment.
Use sequencing tasks for methods (e.g. crystallisation) with “missing step” identification.
Train students to annotate diagrams with functional descriptions (e.g. “filter paper to separate solid from solution”).

Summary: Key Lessons from CIE IGCSE Chemistry Papers 1–6

Examiners highlighted the following strategies to help students gain marks across all papers:

Teach precision in observations and terminology:
From gas tests to precipitation reactions, wording matters. ‘Effervescence’ scores. ‘Gas given off’ does not.
Standardise how data is recorded:
Decimal places must match apparatus resolution. Burette and thermometer readings should be consistent throughout.
Practice full, structured method writing:
Listing apparatus isn't enough. Strong answers explain what’s done, why, and in the right order.
Focus on chemical tests and formula construction:
Tests for ions, gases and naming compounds come up repeatedly. Students need to know reagents, results, and how to write correct formulae.
Strengthen reasoning in multiple choice and theory questions:
MCQ success depends on reading carefully and eliminating distractors. Extended answers should use chemical logic, not vague phrasing.

These strategies are most effective when practised using past paper tasks, model answers, and active recall. This helps students to apply core knowledge confidently across all assessment types.

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