Hello Shainaz,

Important Chapters for Physics

1.    Mechanical Properties of Solids and Fluids

2.    Current Electricity

3.    Dual Nature of Radiation and Matter

4.    Moving Charges and Magnetism

5.    Thermodynamics

6.    Work Energy and Power

7.    Motion in a Plane

8.    Ray Optics and Optical Instruments

9.    Wave Optics

10.    Thermal Properties of Matter

11.    Gravitation

12.    Oscillations

13.    Alternating Current

14.    Waves

15.    Electric Charges and Fields

16.    Semiconductors 

Important Chapters for Chemistry

1.    The S-Block Elements

2.    The P-Block Elements (XI & XII)

3.    The D & F Block Elements

4.    Equilibrium

5.    Basic Concepts of Chemistry

6.    Aldehydes, Ketones & Carboxylic Acids

7.    Chemical Bonding and Molecular Structure

8.    Coordination Compounds

9.    Thermodynamics

10.    Haloalkanes & Haloarenes

11.    Solutions

12.    Alcohols, Phenols & Ethers

Important Chapters for Biology

NO.    ZOOLOGY    BOTANY

1.    Animal Kingdom Biological Classification

2.    Reproduction in Organisms Principles of Inheritance & Variation

3.   Human Health & Disease Morphology of Flowering Plants

4.   Body Fluids and Circulations Cell – The Unit of Life

5.   Neural Control & Coordination Ecosystem

6.   Locomotion and Movement Molecular Basis of Inheritance

7.   Microbes in Human Welfare Biotechnology Principles & Processes

8.   Chemical Coordination & Integration Anatomy of Flowering Plants

9.   Evolution Photosynthesis in Higher Plants

10.  Excretory Products and Their Elimination Organisms & Populations

11.  Structural Organisation in Animals Biotechnology & its Application

12. Digestion and Absorption Strategies for Enhancement in Food Production

For more details please visit the link given down below -

https://medicine.careers360.com/articles/neet-chapter-wise-weightage-and-important-topics

Every chapter is equally important. 

The questions coming in NEET cannot be predicted hence every chapter must be done to score good marks. For example a student wouldn't understand what is Kirchoff's Law if he/she doesn't know what is current, potential difference, etc. 

If you want full portion or have any other queries do mention it in the comment section down below.