• In Physics, Modern Physics take the top slot with 5 questions. Heat and Thermodynamics, Optics, Current Electricity, Elcetrostatics get 3 questions each. Magnetic has 2 questions and the rest get 1 question each.
• In Chemistry, Transition Elements and Coordination Chemistry, Periodic Table and Representative elements take 3 questions slot. Thermodynamics and Gaseous state, Atomic structure, Chemical Bonding, Chemical and Iconic Equilibrium, Solid State and Surface Chemistry and Nuclear Chemistry and Environment get 2 questions slot eacch and the remaining get 1 question each.
• In Mathematics, Co-ordinate Geometry gets 5 questions. Limits, Continuity and Differentiability, Integral Calculus get 3 questions slot each. The rest get 2 and 1 questions slot. For complete breakdown, please read our article:https://engineering.careers360.com/articles/jee-main-syllabus-weightage

There is no specific weightage allotted officially by the JEE, but yes you can say that 3-4 questions may be asked from the P Block Elements topic.

Also you may consider 1-2 questions from the topics like Chemistry in Everyday life and Hydrogen.

These topics don't have much weightage, but also they have few topics to study, so these should not be left out.