Hello aspirant !!

I hope you are doing well. See, if you want to do preparation for jee mains then remember nthe one thing is that try to not leave any chapter as the whole course is important for the exam. You never know which concept or unit will come more. But , as per your mentioned query , i will mention the chapters of chemistry that have high weightage.

• Transition elements and coordination chemistry
• Periodic table and representative elements
• Thermodynamics and gaseous state
• Atomic structure
• Chemical bonding
• Chemical and iconic equilibrium
• Solid state and surface chemistry
• Nuclear chemistry and environment

To know more , visit to the given link :

https://engineering.careers360.com/articles/jee-main-syllabus-weightage

I hope this will be helpful for you.

Good wishes !!

Hello! the most weighed chapters for jee mains are atomic structure, gaseous state,electrochemistry, chemical kinetics, chemical bonding, d block and coordination compunds, alkly halides , thermodynamics, p block, isomerism, aldehydes and ketones and carboxylic acids.

IF u do these you can get a decent score in chemistry section.