CBSE Class 10 Science chapter-wise weightage
What the 2023–2026 board papers actually asked, chapter by chapter.
CBSE gives marks to units, not to chapters. Each unit below shows the marks CBSE’s 2025-26 syllabus gives it, and under it how the marks in the 2023–2026 papers actually split between its chapters.
| Chapter | 2023 | 2024 | 2025 | 2026 | Average |
|---|---|---|---|---|---|
| Chemical Substances-Nature and BehaviourCBSE: 25 of 80 marks (31.3%) · in the papers: 30.5% | |||||
| Chemical Reactions and Equations | 7.0% | 9.3% | 6.3% | 10.3% | 8.2% |
| Acids, Bases and Salts | 7.7% | 7.1% | 6.4% | 6.3% | 6.9% |
| Metals and Non-metals | 7.6% | 8.3% | 8.9% | 6.7% | 7.9% |
| Carbon and its Compounds | 7.0% | 6.5% | 9.1% | 7.4% | 7.5% |
| World of LivingCBSE: 25 of 80 marks (31.3%) · in the papers: 30.1% | |||||
| Life Processes | 10.4% | 9.9% | 10.0% | 10.7% | 10.2% |
| Control and Coordination | 6.1% | 6.2% | 7.1% | 4.6% | 6.0% |
| How do Organisms Reproduce? | 7.9% | 9.1% | 8.3% | 6.6% | 8.0% |
| Heredity | 5.7% | 6.8% | 6.2% | 4.8% | 5.9% |
| Natural PhenomenaCBSE: 12 of 80 marks (15.0%) · in the papers: 14.9% | |||||
| Light - Reflection and Refraction | 9.8% | 6.9% | 9.1% | 9.7% | 8.9% |
| The Human Eye and the Colourful World | 6.7% | 5.9% | 6.0% | 5.5% | 6.0% |
| Effects of CurrentCBSE: 13 of 80 marks (16.3%) · in the papers: 17.2% | |||||
| Electricity | 8.5% | 10.3% | 9.6% | 10.9% | 9.8% |
| Magnetic Effects of Electric Current | 6.6% | 7.1% | 7.9% | 8.1% | 7.4% |
| Natural ResourcesCBSE: 5 of 80 marks (6.3%) · in the papers: 5.8% | |||||
| Our Environment | 7.4% | 5.0% | 5.0% | 5.7% | 5.8% |
| Not in CBSE’s 2025-26 unit marksasked in some of these years; the current syllabus gives them no board-exam marks | |||||
| Periodic Classification of Elements | — | — | 0.1% | — | 0.0% |
How this is counted
From all 1,321 questions in the 2023–2026 CBSE Class 10 Science papers we hold: every region and set, with a question printed in several sets counted once. A chapter’s share is its marks divided by all the marks of that year’s questions, and the average gives each year equal weight. These are observed shares, not an official CBSE weightage. 2022 is left out: it was the Term-II exam, which covered only part of the syllabus (see the 2022 paper).
Unit marks are CBSE’s own, from the 2025-26 syllabus. Where CBSE groups units under one figure, so does this table.