CBSE Class 10 Science: Syllabus, Chapters & Sample Practice

Unit I — Chemical Substances: Nature and Behaviour (25 marks)

• Ch 1 Chemical Reactions and Equations

  Balanced chemical equations; types of reactions — combination, decomposition, displacement, double displacement; oxidation and reduction.

• Ch 2 Acids, Bases and Salts

  Definitions in terms of H⁺ and OH⁻ ions; indicators; the pH scale; preparation and uses of common salts.

• Ch 3 Metals and Non-metals

  Properties; the reactivity series; ionic compounds; basic metallurgical processes; corrosion and its prevention.

• Ch 4 Carbon and its Compounds

  Covalent bonding; versatile nature of carbon; homologous series and nomenclature; ethanol, ethanoic acid, soaps and detergents.

Unit II — World of Living (25 marks)

• Ch 1 Life Processes

  Nutrition, respiration, transport and excretion in plants and animals.

• Ch 2 Control and Co-ordination

  Tropic movements and plant hormones; the nervous system; reflex action; chemical co-ordination through animal hormones.

• Ch 3 Reproduction

  Asexual and sexual reproduction in animals and plants; reproductive health; family planning.

• Ch 4 Heredity

  Mendel's laws for inheritance of traits; sex determination.

Unit III — Natural Phenomena (12 marks)

• Ch 1 Light — Reflection and Refraction

  Reflection by spherical mirrors; the mirror formula and magnification; refraction, refractive index, the lens formula and power of a lens.

• Ch 2 The Human Eye and the Colourful World

  The human eye and defects of vision; refraction through a prism; dispersion and scattering of light.

Unit IV — Effects of Current (13 marks)

• Ch 1 Electricity

  Electric current and potential difference; Ohm's law; resistance and resistivity; series and parallel resistors; heating effect and electric power.

• Ch 2 Magnetic Effects of Electric Current

  Magnetic field due to a current; force on a current-carrying conductor; Fleming's left-hand rule; direct and alternating current; domestic circuits.

Unit V — Natural Resources (5 marks)

• Ch 1 Our Environment

  Ecosystems; environmental problems; ozone depletion; waste production and management; biodegradable and non-biodegradable substances.

Point to the Method

Names the tool to reach for (e.g. "Use Ohm's law, V = IR") without giving the answer.

Guided Reasoning Prompt

Prompts the key idea (e.g. "Which quantities are given, and which one are you solving for?").

Complete Worked Solution

Shows the full step-by-step working and explains why the answer is correct.

Master Equations, Diagrams and Definitions

Balanced chemical equations, ray and circuit diagrams, and precise biology definitions are where marks are won or lost.

Focus Practice on High-Weight Units

Chemical Substances (25) and World of Living (25) together carry half the paper, so steady practice there pays off most.

Use Previous Years’ Papers for Timing

Working past papers under a clock builds exam-day pacing for the 3-hour, 80-mark board paper.

How many units are in the CBSE Class 10 Science syllabus?

The 2026-27 CBSE Class 10 Science syllabus (code 086) has five assessment units: Chemical Substances – Nature and Behaviour, World of Living, Natural Phenomena, Effects of Current, and Natural Resources. Always confirm the current syllabus with CBSE or your school.

How is CBSE Class 10 Science assessed?

An 80-mark board theory paper (3 hours) plus 20 marks of internal assessment — periodic tests, portfolio and practical work — totalling 100.

Which units carry the most marks in Class 10 Science?

Chemical Substances – Nature and Behaviour (25) and World of Living (25) carry the most, followed by Effects of Current (13), Natural Phenomena (12) and Natural Resources (5).

Is there a Standard and an Advanced level for Class 10 Science?

No. CBSE Class 10 Science (code 086) is offered at a single level with no Basic-versus-Standard board split. For 2026-27 an optional "Science at Advanced Level" is published for Grade 9 only. Some topics (such as Periodic Classification of Elements, Heredity and Evolution, and the Motor/Electric Generator) are listed as formative and are not assessed in the year-end paper — confirm the current syllabus with CBSE or your school.