CBSE Class 10 Science Syllabus

How the class 10 science syllabus splits its 80 marks

Notice how lopsided the syllabus of class 10 science is: Units I and II alone are worth 50 of the 80 theory marks. That makes chemistry and biology the backbone of your score, while light and electricity are smaller units with tougher numericals.

Chapter list with key topics

Chemistry

• Chemical reactions and equations: balancing, combination, decomposition, displacement, double displacement, redox, corrosion and rancidity
• Acids, bases and salts: indicators, pH scale, reactions with metals and carbonates, common salts such as baking soda, washing soda, bleaching powder and plaster of Paris
• Metals and non metals: physical and chemical properties, reactivity series, ionic compounds, extraction basics, corrosion prevention
• Carbon and its compounds: covalent bonding, homologous series, functional groups, nomenclature, combustion, oxidation, ethanol and ethanoic acid, soaps and detergents

Biology

• Life processes: nutrition, respiration, transport and excretion in plants and humans
• Control and coordination: reflex action, human brain, plant hormones and tropic movements, the endocrine system
• How do organisms reproduce: asexual methods, sexual reproduction in flowering plants and humans, reproductive health
• Heredity: Mendel's experiments, inheritance of traits, sex determination

Physics

• Light, reflection and refraction: spherical mirrors and lenses, sign convention, mirror and lens formulas, magnification, power of a lens, refractive index
• The human eye and the colourful world: defects of vision and correction, refraction through a prism, dispersion, scattering of light
• Electricity: Ohm's law, resistance and resistivity, series and parallel combinations, heating effect, electric power
• Magnetic effects of electric current: field lines, field due to a straight wire, loop and solenoid, force on a current carrying conductor, domestic circuits

Environment

• Our environment: ecosystems, food chains and webs, trophic levels, ozone depletion, waste management

Marking scheme of science class 10 board paper

The latest CBSE sample paper for class 10 science still has 39 compulsory questions for 80 marks, and a number of them offer an internal choice. What changed is the layout: the paper and the answer book are now split by subject instead of by question type.

• Section A, Biology, 30 marks: 16 questions covering the world of living unit and the environment chapter
• Section B, Chemistry, 25 marks: 13 questions on the four chemistry chapters
• Section C, Physics, 25 marks: 10 questions on light, the eye, electricity and magnetic effects

Across the three sections the mix of items is the same as before: twenty one mark objective items (a few framed as assertion and reason pairs), six two mark answers, seven three mark answers, three four mark case studies and three five mark answers. Answer every question in its own subject's part of the answer book; CBSE does not evaluate answers written in another part.

A large share of the paper is competency based, meaning questions set in real situations or data rather than direct recall. Section-wise counts can shift slightly between sessions, so look at the latest sample paper on the board's academic website.

Internal assessment and practicals

The 20 internal marks come from your school. As per the CBSE curriculum, periodic assessment carries 10 (5 plus 5), subject enrichment through practical work carries 5 and your portfolio of class work carries 5. Your teacher records these through the year.

Lab activities listed in the syllabus include finding the pH of samples with pH paper or universal indicator, studying the properties of acids and bases, observing types of chemical reactions, checking the reactivity of metals with salt solutions, verifying Ohm's law, finding the focal length of a concave mirror and a convex lens, tracing the path of light through a glass slab and a prism, preparing a leaf peel to see stomata, showing that carbon dioxide is released in respiration and observing binary fission and budding on slides. Questions on these practicals also appear in the theory paper, so keep a short note of each aim, procedure and result.

What was removed and what stays

Since the NCERT book was rationalised, several older chapters are no longer in the class 10 science book: periodic classification of elements, sources of energy and sustainable management of natural resources are gone, and evolution was trimmed from the heredity chapter. If you are using an old guide or an older sibling's book, skip those parts unless your current curriculum lists them again. The NCERT syllabus for class 10 science and the CBSE curriculum now line up chapter for chapter.

Where to put your hours

Start with the chapters that give the most marks per hour of study. Carbon compounds and life processes are long but heavily weighted. Chemical reactions and acids, bases and salts are short and scoring. Light carries numericals that repeat in format every year, so practise mirror and lens formula sums until they are routine.

Draw the diagrams the syllabus names, such as the human heart, nephron, brain, flower parts, ray diagrams and the field lines around a solenoid, at least three times each before the board exam. Labelled diagrams often decide whether a 3 mark answer gets full marks.

Books and resources to use

For the CBSE 10th science syllabus, the NCERT textbook is the base, and almost every board question can be answered from it. The NCERT exemplar adds harder MCQs and reasoning questions. The board's sample paper and marking scheme show how answers are graded. Once you finish the syllabus, solve old board papers with the help of our class 10 science previous year papers guide.

Moving on to other subjects? Open the complete CBSE class 10 syllabus overview, the CBSE class 10 maths syllabus, or browse all school board pages.