The CBSE Class 10 Science Marks Distribution 2026-27 is an important reference for students preparing for the CBSE Board Examinations 2027. Understanding the unit-wise weightage, theory paper marks, internal assessment and question paper design can help students plan their revision and focus on the topics prescribed for the current academic session.
The Central Board of Secondary Education (CBSE) has released the Class 10 Science curriculum for 2026-27. As per the official syllabus, the Science subject carries 100 marks, comprising an 80-mark annual theory examination and 20 marks for internal assessment. The theory paper is conducted for three hours.
The syllabus divides the theory examination into five units, with Chemical Substances – Nature and Behaviour and World of Living carrying the highest weightage of 25 marks each. Students should check the latest unit-wise marks distribution and syllabus carefully instead of relying on chapter-wise weightage estimates or previous-year patterns.
Also Check: CBSE 10th Science Syllabus 2026-27
CBSE Class 10 Science Unit-Wise Marks Distribution 2026-27
According to the official CBSE Class 10 Science curriculum, the 80-mark theory paper is divided into five units. Each unit carries a specific weightage, which students can use as a reference while preparing for the board examination.
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Unit No.
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Unit Name
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Marks
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Unit I
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Chemical Substances - Nature and Behaviour
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25
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|
Unit II
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World of Living
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25
|
|
Unit III
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Natural Phenomena
|
12
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|
Unit IV
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Effects of Current
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13
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Unit V
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Natural Resources
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5
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Total
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Theory Examination
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80
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|
Internal Assessment
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20
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|
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Grand Total
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100
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CBSE Class 10 Science Chapter-Wise Weightage 2026-27
CBSE provides the marks distribution at the unit level rather than assigning a fixed number of marks to every individual chapter. Therefore, students should not treat chapter-wise weightage tables circulating online as an official board allocation.
The following table maps the prescribed chapters and topics to their respective units to help students organise their revision.
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Unit
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Major Chapters and Topics
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Unit Marks
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Chemical Substances- Nature and Behaviour
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Chemical Reactions and Equations; Acids, Bases and Salts; Metals and Non-metals; Carbon and its Compounds
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25
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World of Living
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Life Processes; Control and Coordination; Reproduction; Heredity
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25
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Natural Phenomena
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Light – Reflection and Refraction; Human Eye and the Colourful World
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12
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Effects of Current
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Electricity; Magnetic Effects of Electric Current
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13
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Natural Resources
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Our Environment
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5
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CBSE Class 10 Science Internal Assessment Marks Distribution 2026-27
Apart from the annual theory examination, students have to complete the internal assessment, which carries 20 marks. This component evaluates students' regular academic performance, practical understanding, participation in different assessments and subject-related activities.
CBSE has prescribed the following internal assessment structure for Class 10 Science in the 2026-27 session:
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Internal Assessment Component
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Marks
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Periodic Assessment
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5
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Multiple Assessment
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5
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Portfolio
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5
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Subject Enrichment (Practical Work)
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5
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Total
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20
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CBSE Class 10 Science Question Paper Design 2027
The CBSE Class 10 Science theory paper carries 80 marks and is designed to evaluate student’s conceptual understanding, application skills and analytical abilities. As per the official 2026-27 curriculum, the question paper design follows this competency-wise distribution:
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Competency
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Weightage
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Marks
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Demonstrate Knowledge and Understanding
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50%
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40
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Application of Knowledge/Concepts
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30%
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24
|
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Formulate, Analyse, Evaluate and Create
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20%
|
16
|
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Total
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100%
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80
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