Most Important Chapters — Class 10 Science
Class 10 Science theory is 80 marks. Chemistry and Biology each carry 25 — half the paper.
TL;DR: Class 10 Science theory is 80 marks. Chemistry and Biology each carry 25 — half the paper.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Class 10 Science theory is 80 marks. Chemistry and Biology each carry 25 — half the paper.
Class 10 Science — Unit-wise Marks Weightage
CBSE Board — 80 marks in theory, listed heaviest first so you can see where your revision time actually earns marks.
| Unit | Marks | Share | What to focus on |
|---|---|---|---|
| Chemical Substances – Nature & Behaviour | 25 | 31% | Acids-bases-salts, metals/non-metals, carbon compounds, periodic table. |
| World of Living (Biology) | 25 | 31% | Life processes, control & coordination, reproduction, heredity. |
| Effects of Current | 13 | 16% | Electricity and magnetic effects — Ohm’s law numericals are guaranteed. |
| Natural Phenomena (Light & Eye) | 12 | 15% | Reflection, refraction, lenses, human eye — numericals + ray diagrams. |
| Natural Resources | 5 | 6% | Our environment and management — short, scoring. |
How to Use This Weightage
Work down the table rather than through the textbook in order. Chemical Substances – Nature & Behaviour and World of Living (Biology) alone account for 50 of 80 marks, so a week spent there moves your score further than a week spent on the last three units combined. Once the heavy units are secure, the lighter ones are usually short and formula-driven, which makes them efficient to finish last.
Treat the tips in the final column as the specific sub-topics examiners return to. They are where the marks in each unit actually sit.
Frequently Asked Questions
Which chapters carry the most marks in Class 10 Science?
Chemical Substances – Nature & Behaviour (25 marks) and World of Living (Biology) (25 marks) carry the most — 50 of 80 between them. Securing these two before anything else is the single highest-return decision in your revision plan.
What is the total marks for Class 10 Science?
CBSE Board carries 80 marks in theory. The unit-wise split above accounts for all of them.
Should I skip the low-weightage units?
No. The smallest units here are worth 5 marks, which is more than the gap between most grade boundaries, and they are usually the quickest to prepare. Order your revision by weightage; do not delete anything from it.