To score good marks in the exam firstly I would suggest you to go through with NCERT books as it will help you to clear the basic concepts. The Chemistry section in NEET will consist 45 questions. Here are some of teh topics you can prefer:

Basic Concepts of Chemistry
   
Structure of Atom

Classification of Elements & Periodicity in Properties
   
Chemical Bonding and Molecular Structure
   
States of Matter: Gases and Liquids
   
Thermodynamics

Equilibrium

Redox Reactions

Hydrogen

s-Block Elements

Some p-Block Elements

Organic Chemistry: Basic Principles & Techniques

Hydrocarbons

Environmental Chemistry

You can check the complete detail & weightage chapter wise with the given below link.

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

Good Luck!

mostly the questions in chemistry are one word or two line answers and that to cover the entire syllabus you can see the chapter wise distribution for board exam and then sold the previous years question because they are the key to success most of the questions were simply from the previous years therefore do not forget to prepare previous question