Hi Shivam,

All the chapters in chemistry has a good weightage for JEE Mains. All the chapters are very important and you need to two factors for each and every topic in chemistry or any other subject.

1) Transition elements and coordination chemistry are off 12 marks which have 3 questions.

2) Periodic table and representative elements are also of 12th marks with 3 questions.

3) Thermodynamics and gaseous state are of 8 marks with 2 questions.

For more information can go to the link given below.

Link :- https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-syllabus-weightage/amp

I hope your question has been answered properly.

All the best for your future!