Cambridge IGCSE Chemistry 0620/32 is the May/June 2026 Paper 3 (Core Theory), variant 2. It lasts 1 hour 15 minutes, is worth 80 marks and is sat by every Core candidate. It had seven compulsory questions, and one of them, on nickel and its compounds, carried 20 marks. This guide goes through the paper question by question and shows what the official mark scheme gave marks for. The paper and its mark scheme are free on the Tutopiya Learning Portal.

For an overview of all six 0620 papers from this series, see IGCSE Chemistry 0620 May/June 2026 past papers: what came up and how it was marked.

0620/32 at a glance

Question	Topic	Marks	Main command word
1	Identifying six substances from their structures	9	State
2	Group I elements, the test for hydrogen, bonding in ammonia	10	Predict, deduce
3	Magnesium carbonate and sulfuric acid: a volume–time graph, rates, acids	11	State, deduce
4	Organic compounds, fermentation, ethanoic acid	9	State, outline
5	States of matter, changes of state, diffusion	9	Complete, state
6	Nickel: atomic structure, ionic bonding, electrolysis, Mr, alloys	20	State, name
7	Water: pollution, the flame test, a reacting-mass ratio, water treatment	12	State
	Total	80

Question-by-question walkthrough

Question 1: identifying substances (9 marks)

Six substances, A to F, were shown as structures or formulas: ethane, carbon dioxide, chlorine, propanoic acid, nitrogen and ethanol.

• Seven one-word answers (7 × 1 mark): the alcohol was F, the gas that makes up about 78% of air was E (nitrogen), the compound in the same homologous series as ethanoic acid was D, the hydrocarbon was A, and B (carbon dioxide) answered both the combustion-product question and the limewater question. The pale yellow-green gas was C (chlorine). A correct formula was also accepted in place of the letter, and names were ignored.
• The two elements (2 marks): C and E, chlorine and nitrogen. Students who think “element” means “single atom” can miss that diatomic molecules such as N₂ and Cl₂ are still elements.

Question 2: Group I elements (10 marks)

A table gave melting point, boiling point and atomic radius for lithium, sodium, potassium and rubidium, with some values missing.

• Predict two missing values (2 × 1 mark): the melting point of sodium had to fall between 75 °C and 170 °C, and the atomic radius of potassium between 190 and 245 pm. Any value inside the trend scored; units were ignored for the radius.
• State of lithium at 95 °C (2 marks): solid, because 95 °C is below its melting point of 180 °C. The two marks are independent. Quoting the numbers without comparing them was ignored, so say which is lower.
• Density down the group (1 mark): it increases.
• Balancing potassium with water (2 marks): 2K + 2H₂O → 2KOH + H₂, one mark per coefficient.
• Test for hydrogen (1 mark): a lighted splint gives a (squeaky) pop. A glowing splint was rejected, because that is the test for oxygen.
• Dot-and-cross diagram for ammonia (2 marks): one shared pair between nitrogen and each hydrogen, and a lone pair (two non-bonding electrons) on the nitrogen, with no extra electrons on the hydrogens. Electrons could all be dots, all crosses or a mix.

Question 3: magnesium carbonate and sulfuric acid (11 marks)

• State symbol (s) (1 mark): solid.
• Name the salt (1 mark): magnesium sulfate, spelt correctly (sulfate or sulphate).
• Apparatus to collect and measure the gas (1 mark): a gas syringe. A measuring cylinder or burette over water was accepted, but a plain “measuring cylinder” was not enough.
• Reading the graph (2 × 1 mark): 26 cm³ of carbon dioxide after 20 s, and the reaction finished at 45 s (44 to 45 s accepted).
• Sketching the line for smaller pieces (2 marks): one mark for a steeper line starting at the origin, and one for levelling off at the same final volume, 40 cm³, before 40 s, without touching the original curve on the way. The acid volume is unchanged and the carbonate is in excess, so the total gas cannot change.
• Higher temperature and lower acid concentration (2 × 1 mark): the rate is faster, then slower. These had to be comparative; comments on time or gas volume were ignored.
• The ion in all acids (1 mark): H⁺. A lower-case “h+” was rejected.
• An acidic pH (1 mark): pH 2.

Question 4: organic compounds (9 marks)

Compound P was a saturated five-carbon molecule with a carboxylic acid group at one end and an alcohol group at the other.

• Circle the alcohol group (1 mark): the –OH at the alcohol end, not the –OH inside the –COOH group.
• Molecular formula (1 mark): C₅H₁₀O₃, in any order.
• Why P is saturated (1 mark): it has only carbon–carbon single bonds (or no C=C double bonds). “Single bonds” without mentioning carbon was ignored.
• Making ethanol from aqueous glucose (3 marks): fermentation, plus any two conditions: 25–35 °C, yeast, and the absence of oxygen. A temperature range was rejected if either end fell outside the accepted range, and “warm” was ignored.
• A use of ethanol (1 mark): solvent or fuel. “To drink” was ignored.
• Ethanoic acid with magnesium (2 marks): magnesium ethanoate and hydrogen. Ethanoate had to be spelt correctly.

Question 5: states of matter (9 marks)

• Two properties of a liquid (2 marks): any two from a fixed volume, taking the shape of its container, flowing, and not being compressible. Answers about particle arrangement were ignored here.
• Particle motion and separation table (4 marks): solid particles vibrate and are touching or very close; liquid particles slide over each other and are also touching or close. “Apart”, “separated” or “spaces” (unqualified) were rejected for the liquid, because liquid particles are still close together.
• Matching changes of state (2 marks): liquid nitrogen to solid is freezing, liquid cobalt to gas is evaporating, and steam to liquid water is condensing. All three correct scored 2.
• Gas particles spreading out (1 mark): diffusion.

Question 6: nickel (20 marks)

• Period number (1 mark): Period 4.
• Particles in the Ni²⁺ ion (3 marks): with mass number 60 and proton number 28, there are 28 protons, 32 neutrons and 26 electrons. The 2+ charge means two electrons lost, which is where marks slip.
• Meaning of ionic bond (2 marks): a (strong) electrostatic attraction, between oppositely charged ions.
• Two physical properties of ionic compounds (2 marks): a high melting or boiling point, conducting electricity when molten or in aqueous solution, and being soluble in water. “Conducts when solid” was rejected.
• Nickel with oxygen (2 marks): 2Ni + O₂ → 2NiO, one mark for each part. “2O₂” was rejected.
• Acidic or basic oxide (1 mark): basic, because nickel is a metal.
• An inert non-metal electrode (1 mark): carbon (graphite).
• Electrolysis of molten nickel(II) bromide (3 marks): nickel at the negative electrode, bromine at the positive electrode, and a red-brown liquid or brown vapour seen at the positive electrode. Writing “bromide” for the product was rejected, and the right products at the wrong electrodes scored only 1.
• Mr of Ni(OH)₂ (2 marks): 59 + (2 × 16) + (2 × 1) = 93. If the total was wrong, O = 32 or H = 2 still earned one mark.
• Meaning of alloy (1 mark): a mixture of a metal with another element. Saying the elements are “bonded” or “chemically combined” was rejected, because an alloy is a mixture.
• Two other elements in stainless steel (2 marks): any two from chromium, iron and carbon.

Question 7: water (12 marks)

• Source of nitrate pollution (1 mark): fertilisers (sewage or manure also accepted).
• Why nitrates are harmful (1 mark): they lead to deoxygenation of the water; eutrophication was accepted. “Kills marine life” and “growth of algae” were ignored.
• Why some metal compounds are harmful (1 mark): they are toxic (poisonous). Only this idea scored.
• Test for potassium ions (2 marks): a flame test, giving a lilac (or purple) flame. The word “flame” had to appear somewhere.
• Reacting-mass ratio (1 mark): 6.6 g is half of 13.2 g, so the mass of potassium iodide is half of 56.2 g, 28.1 g.
• Three water-treatment stages (3 marks): sedimentation and filtration remove solids, carbon removes tastes and odours (or colour), and chlorination kills microbes.
• Why distilled water is used (1 mark): it contains fewer impurities. “Cleaner” was ignored.
• Anhydrous cobalt(II) chloride with water (2 marks): blue to pink. The reverse, pink to blue, scored only 1.

Where the marks are on 0620/32

• “State” questions carried 33 of the 80 marks. These are short recall answers, and Question 1 alone was nine of them.
• “Name” carried 11 marks and “complete” carried 14 marks (the equations, the dot-and-cross diagram, the particle table, the word equation and the Mr table).
• Predict, deduce and determine carried 10 marks, all of them reading or reasoning from data you were given: the Group I table, the rate graph, the displayed formula and the Ni²⁺ symbol.
• Drawing carried 5 marks (the rate-graph line, the circle and the matching lines), the fermentation outline carried 3, and calculate, explain, write and choose carried 1 mark each.
• Question 6 alone is worth 20 marks. If metals, bonding and electrolysis are weak areas, they cost more on this paper than any other topic.

How to self-mark 0620/32 with the mark scheme

1. Learn the abbreviations first. ALLOW means accept, IGNORE means the words neither gain nor lose the mark, REJECT means the answer scores nothing, and NOTE gives the examiner extra guidance. A slash separates alternatives for the same point.
2. Mark point by point. For Question 2(a)(iii), the state and the reason are independent marks, so you can score one without the other.
3. Read the reject list. “Glowing splint” in 2(b)(ii), “conducts when solid” in 6(b)(ii) and “chemically combined” in 6(f)(i) all sound close but scored nothing.
4. Check spelling where it is marked. Sulfate in 3(a)(ii) and ethanoate in 4(c) needed correct spelling.
5. Apply the list rule. For “state two” questions such as 5(a) and 6(b)(ii), mark only your first two answers. A wrong answer still uses up a place.
6. Check your drawn line in 3(b)(iii) against both criteria: steeper from the origin, and level at 40 cm³ before 40 s.
7. Log each lost mark as missing knowledge, a misread command word or a careless slip, and revise in that order.

Sit 0620/32 as a timed mock

The paper allows 75 minutes for 80 marks, a little under one minute per mark. A workable plan:

Block	Marks	Time
Question 1	9	8 minutes
Question 2	10	9 minutes
Question 3	11	10 minutes
Question 4	9	8 minutes
Question 5	9	8 minutes
Question 6	20	18 minutes
Question 7	12	11 minutes
Check, especially equations, spellings and units	–	3 minutes

Question 1 is quick recall, so bank the time there for the 20-mark nickel question.

Other May/June 2026 0620 papers

• 0620 Paper 12 (Core Multiple Choice)
• 0620 Paper 22 (Extended Multiple Choice)
• 0620 Paper 42 (Extended Theory)
• 0620 Paper 52 (Practical Test)
• 0620 Paper 62 (Alternative to Practical)

Practise and download

• Download 0620/32 and its mark scheme on the Learning Portal →
• All 0620 May/June 2026 papers: overview and marking patterns
• Try a free IGCSE Chemistry quiz

Need help with a 0620 topic? Book a free trial lesson with an IGCSE Chemistry tutor →

Frequently asked questions

What topics were on 0620 Paper 32 May/June 2026? +

Seven questions: identifying substances from their structures; Group I elements and ammonia bonding; magnesium carbonate with sulfuric acid and a rate graph; organic compounds and fermentation; states of matter; nickel and its compounds; and water pollution, testing and treatment.

How many marks is 0620/32 and how long is it? +

It is out of 80 marks and lasts 1 hour 15 minutes. Question 6, on nickel, is the biggest at 20 marks.

What was the answer to the potassium iodide calculation in 0620/32? +

13.2 g of potassium gives 56.2 g of potassium iodide, so half the potassium (6.6 g) gives half the product: 28.1 g. It was worth one mark.

What was the relative formula mass of Ni(OH)2 in 0620/32? +

93. That is 59 for nickel, 2 × 16 = 32 for oxygen and 2 × 1 = 2 for hydrogen. If the total was wrong, one mark was still available for O = 32 or H = 2.

Is 0620/32 the Core or Extended paper? +

Core. Paper 3 is the Core theory paper, sat alongside Paper 1 (Core multiple choice) and either Paper 5 or Paper 6. Extended candidates sit Paper 4 instead.

Where can I download 0620/32 May/June 2026 and its mark scheme? +

Both are free to download and print on the Tutopiya Learning Portal, on the Cambridge IGCSE Chemistry 0620 past papers page.

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