Which topic comes up most in IGCSE Chemistry 0620?

Organic chemistry. It carries 18.4% of the Paper 2 and Paper 4 marks in our bank, followed by Atoms, elements and compounds (13.6%).

How many chapters do you need for most of the marks?

8 of the 12 chapters carry 80% of the marks between them. States of matter carries the fewest, at 2.5%.

Which subtopics are asked most?

Reversible reactions and equilibrium (6.3, 6.4%), The mole and the Avogadro constant (3.3, 5.2%) and Electrolysis (4.1, 4.7%).

How were these numbers counted?

From every question in the Zainora Chemistry bank: 4,283 multiple-choice questions from 110 Paper 2s, 2010–2026, and 8,178 theory marks from 107 theory papers, 2010–2025, each part filed under the chapter it tests. The two papers are weighted as Cambridge weights them, 30% and 50% of the grade.

Cambridge IGCSE Chemistry 0620 · counted from the past papers

Which topics come up most in Chemistry?

We counted every question in the Zainora Chemistry bank, 4,283 multiple-choice questions and 8,178 theory marks, and filed each one under the chapter it tests. 8 of the 12 chapters carry 80% of the marks.

Practise Chemistry by topic Chemistry papers and tools

What the numbers say

Organic chemistry carries the most marks in Chemistry 0620: 18.4% of the Paper 2 and Paper 4 marks, ahead of Atoms, elements and compounds (13.6%) and Chemical reactions (13.2%).
4 of the 12 chapters hold half the marks, and 8 hold 80%. States of matter is the lightest at 2.5%: revise it last, but do not drop it, because Cambridge can set anything on the syllabus.
Organic chemistry came up in every one of the 107 theory papers we have, 2010–2025.
The Periodic Table is worth more on Paper 2 than on Paper 4 (9.1% of the multiple-choice questions against 5.0% of the theory marks), so practise it as quick multiple-choice questions.
Stoichiometry is the other way round: 9.7% of the theory marks but 4.8% of the multiple-choice questions. Learn to write it out in full.
Chemical energetics has the longest theory answers, 2.1 marks a part on average, so its questions need method and working, not a one-line answer.

Every chapter, most marks first

Paper 2 30% · Paper 4 50%

The bar is the chapter's share of the marks, with the multiple-choice and theory papers weighted the way Cambridge weights them in your grade. "In 107 of 107 papers" means the chapter was asked at least once in that many papers.

#Chapter · share of the marksPaper 2Theory
1
Organic chemistry
Ch. 11
18.4%
Paper 2
705 questions · 16.5%in 110 of 110 papers
Theory
1,605 marks · 19.6%in 107 of 107 papers
Practise
2
Atoms, elements and compounds
Ch. 2
13.6%
Paper 2
489 questions · 11.4%in 110 of 110 papers
Theory
1,219 marks · 14.9%in 102 of 107 papers
Practise
3
Chemical reactions
Ch. 6
13.2%
Paper 2
470 questions · 11.0%in 110 of 110 papers
Theory
1,192 marks · 14.6%in 103 of 107 papers
Practise
4
Metals
Ch. 9
9.7%
Paper 2
490 questions · 11.4%in 110 of 110 papers
Theory
715 marks · 8.7%in 95 of 107 papers
Practise
5
Acids, bases and salts
Ch. 7
9.0%
Paper 2
388 questions · 9.1%in 110 of 110 papers
Theory
735 marks · 9.0%in 98 of 107 papers
Practise
6
Stoichiometry
Ch. 3
7.9%
Paper 2
204 questions · 4.8%in 104 of 110 papers
Theory
797 marks · 9.7%in 102 of 107 papers
Practise
7
The Periodic Table
Ch. 8
6.5%
Paper 2
391 questions · 9.1%in 110 of 110 papers
Theory
408 marks · 5.0%in 82 of 107 papers
Practise
8
Chemistry of the environment
Ch. 10
5.7%
Paper 2
338 questions · 7.9%in 109 of 110 papers
Theory
362 marks · 4.4%in 81 of 107 papers
Practise
9
Experimental techniques and chemical analysis
Ch. 12
5.4%
Paper 2
294 questions · 6.9%in 110 of 110 papers
Theory
369 marks · 4.5%in 84 of 107 papers
Practise
10
Electrochemistry
Ch. 4
5.3%
Paper 2
215 questions · 5.0%in 110 of 110 papers
Theory
448 marks · 5.5%in 66 of 107 papers
Practise
11
Chemical energetics
Ch. 5
2.6%
Paper 2
163 questions · 3.8%in 102 of 110 papers
Theory
159 marks · 1.9%in 38 of 107 papers
Practise
12
States of matter
Ch. 1
2.5%
Paper 2
136 questions · 3.2%in 108 of 110 papers
Theory
169 marks · 2.1%in 45 of 107 papers
Practise

The ten biggest syllabus points

Inside the chapters, these are the parts of the syllabus Cambridge asks about most.

1
6.3Reversible reactions and equilibrium
Chemical reactions · 204 MCQs · 597 theory marks
6.4%
2
3.3The mole and the Avogadro constant
Stoichiometry · 103 MCQs · 564 theory marks
5.2%
3
4.1Electrolysis
Electrochemistry · 182 MCQs · 412 theory marks
4.7%
4
6.2Rate of reaction
Chemical reactions · 128 MCQs · 416 theory marks
4.3%
5
10.3Air quality and climate
Chemistry of the environment · 210 MCQs · 291 theory marks
4.1%
6
7.1The characteristic properties of acids and bases
Acids, bases and salts · 208 MCQs · 289 theory marks
4.0%
7
11.8Polymers
Organic chemistry · 118 MCQs · 383 theory marks
4.0%
8
9.6Extraction of metals
Metals · 115 MCQs · 355 theory marks
3.7%
9
7.3Preparation of salts
Acids, bases and salts · 94 MCQs · 332 theory marks
3.4%
10
11.1Formulae, functional groups and terminology
Organic chemistry · 119 MCQs · 305 theory marks
3.4%

What came up each year

Each cell is the chapter's share of that year's theory marks, in percent, across every session and variant we have. A chapter that is dark in every column is asked every year.

Share of each year's Chemistry theory marks, by chapter, 2010 to 2025
Chapter	10 (2010)	11 (2011)	12 (2012)	13 (2013)	14 (2014)	15 (2015)	16 (2016)	17 (2017)	18 (2018)	19 (2019)	20 (2020)	21 (2021)	22 (2022)	23 (2023)	24 (2024)	25 (2025)
1States of matter	3	–	4	0	3	2	4	3	2	2	3	3	1	0	2	2
2Atoms, elements and compounds	12	8	12	14	8	13	19	20	11	18	16	16	18	15	14	20
3Stoichiometry	9	4	4	7	6	10	12	12	14	13	10	12	12	7	13	10
4Electrochemistry	6	3	8	3	6	3	5	6	8	7	5	9	3	5	6	4
5Chemical energetics	1	1	1	1	1	1	1	3	2	3	2	2	4	2	1	5
6Chemical reactions	19	19	15	19	17	13	14	12	14	11	13	11	14	18	14	15
7Acids, bases and salts	7	10	9	9	8	12	8	8	9	9	7	8	8	12	12	8
8The Periodic Table	5	5	7	4	7	4	4	2	4	5	6	5	6	5	3	8
9Metals	12	14	11	11	14	10	7	7	7	6	8	6	4	10	10	6
10Chemistry of the environment	3	7	4	7	5	10	5	4	4	4	3	3	4	5	2	2
11Organic chemistry	21	24	22	23	22	19	16	20	19	17	21	19	18	18	20	18
12Experimental techniques and chemical analysis	3	4	3	2	4	3	5	4	7	6	6	6	9	3	5	2

Every chapter, syllabus point by syllabus point

In syllabus order. Open a chapter to see where its marks sit.

1States of matter2.5%

Syllabus point	MCQs	Theory marks	Share
1.1Solids, liquids and gases	70	110	1.4%
1.2Diffusion	66	59	1.0%

Practise States of matter →

2Atoms, elements and compounds13.6%

Syllabus point	MCQs	Theory marks	Share
2.1Elements, compounds and mixtures	15	23	0.3%
2.2Atomic structure and the Periodic Table	102	302	3.2%
2.3Isotopes	82	172	2.0%
2.4Ions and ionic bonds	81	254	2.6%
2.5Simple molecules and covalent bonds	98	222	2.5%
2.6Giant covalent structures	73	138	1.7%
2.7Metallic bonding	38	108	1.1%

Practise Atoms, elements and compounds →

3Stoichiometry7.9%

Syllabus point	MCQs	Theory marks	Share
3.1Formulae	66	213	2.2%
3.2Relative masses of atoms and molecules	35	20	0.4%
3.3The mole and the Avogadro constant	103	564	5.2%

Practise Stoichiometry →

4Electrochemistry5.3%

Syllabus point	MCQs	Theory marks	Share
4.1Electrolysis	182	412	4.7%
4.2Hydrogen–oxygen fuel cells	33	36	0.6%

Practise Electrochemistry →

5Chemical energetics2.6%

Syllabus point	MCQs	Theory marks	Share
5.1Exothermic and endothermic reactions	163	159	2.6%

Practise Chemical energetics →

6Chemical reactions13.2%

Syllabus point	MCQs	Theory marks	Share
6.1Physical and chemical changes	22	8	0.3%
6.2Rate of reaction	128	416	4.3%
6.3Reversible reactions and equilibrium	204	597	6.4%
6.4Redox	116	171	2.3%

Practise Chemical reactions →

7Acids, bases and salts9.0%

Syllabus point	MCQs	Theory marks	Share
7.1The characteristic properties of acids and bases	208	289	4.0%
7.2Oxides	86	114	1.6%
7.3Preparation of salts	94	332	3.4%

Practise Acids, bases and salts →

8The Periodic Table6.5%

Syllabus point	MCQs	Theory marks	Share
8.1Arrangement of elements	122	64	1.6%
8.2Group I properties	63	82	1.2%
8.3Group VII properties	58	115	1.4%
8.4Transition elements	79	119	1.6%
8.5Noble gases	69	28	0.8%

Practise The Periodic Table →

9Metals9.7%

Syllabus point	MCQs	Theory marks	Share
9.1Properties of metals	49	39	0.7%
9.2Uses of metals	54	35	0.7%
9.3Alloys and their properties	76	57	1.1%
9.4Reactivity series	105	130	1.9%
9.5Corrosion of metals	91	99	1.5%
9.6Extraction of metals	115	355	3.7%

Practise Metals →

10Chemistry of the environment5.7%

Syllabus point	MCQs	Theory marks	Share
10.1Water	82	50	1.1%
10.2Fertilisers	46	21	0.6%
10.3Air quality and climate	210	291	4.1%

Practise Chemistry of the environment →

11Organic chemistry18.4%

Syllabus point	MCQs	Theory marks	Share
11.1Formulae, functional groups and terminology	119	305	3.4%
11.2Naming organic compounds	26	100	1.0%
11.3Fuels	110	69	1.5%
11.4Alkanes	55	105	1.3%
11.5Alkenes	86	241	2.6%
11.6Alcohols	108	171	2.3%
11.7Carboxylic acids	83	231	2.5%
11.8Polymers	118	383	4.0%

Practise Organic chemistry →

12Experimental techniques and chemical analysis5.4%

Syllabus point	MCQs	Theory marks	Share
12.1Experimental design	75	40	1.0%
12.2Acid–base titrations	6	15	0.2%
12.3Chromatography	70	56	1.0%
12.4Separation and purification	70	106	1.4%
12.5Identification of ions and gases	73	152	1.8%

Practise Experimental techniques and chemical analysis →

Common questions

Which topic comes up most in IGCSE Chemistry 0620?: Organic chemistry. It carries 18.4% of the Paper 2 and Paper 4 marks in our bank, followed by Atoms, elements and compounds (13.6%).
How many chapters do you need for most of the marks?: 8 of the 12 chapters carry 80% of the marks between them. States of matter carries the fewest, at 2.5%.
Which subtopics are asked most?: Reversible reactions and equilibrium (6.3, 6.4%), The mole and the Avogadro constant (3.3, 5.2%) and Electrolysis (4.1, 4.7%).
How were these numbers counted?: From every question in the Zainora Chemistry bank: 4,283 multiple-choice questions from 110 Paper 2s, 2010–2026, and 8,178 theory marks from 107 theory papers, 2010–2025, each part filed under the chapter it tests. The two papers are weighted as Cambridge weights them, 30% and 50% of the grade.

How we counted

Paper 2 · Multiple choice: 4,283 questions from 110 papers, 2010–2026. One question is one mark.
Paper 4 · Theory (Paper 3 before 2016): 4,710 parts worth 8,178 marks from 107 papers, 2010–2025. Each part (a), (b)(i) and so on is filed under the chapter it tests, not the chapter its question started in.
Questions on content the current syllabus has dropped are left out: 117 multiple-choice questions and 234 theory parts.
The share weights Paper 2 at 30% and Paper 4 at 50%, as the syllabus does. Paper 6 (Alternative to Practical, 20%) is not counted here. "Since 2021" is the last five years of each paper.
Counted on 1 November 2026 from the same questions you practise in the bank. You may reuse these figures with credit to Zainora (CC BY 4.0).

What the numbers say

Every chapter, most marks first

Organic chemistry

Atoms, elements and compounds

Chemical reactions

Metals

Acids, bases and salts

Stoichiometry

The Periodic Table

Chemistry of the environment

Experimental techniques and chemical analysis

Electrochemistry

Chemical energetics

States of matter

The ten biggest syllabus points

What came up each year

Every chapter, syllabus point by syllabus point

Common questions

How we counted

Other subjects

What the numbers say

Every chapter, most marks first

Organic chemistry

Atoms, elements and compounds

Chemical reactions

Metals

Acids, bases and salts

Stoichiometry

The Periodic Table

Chemistry of the environment

Experimental techniques and chemical analysis

Electrochemistry

Chemical energetics

States of matter

The ten biggest syllabus points

What came up each year

Every chapter, syllabus point by syllabus point

Common questions

How we counted

Other subjects