In Chemistry, there are mainly 3 important parts.  That is Physical chemistry, Organic Chemistry and Inorganic chemistry.

The main topics to cover under Physical Chemistry are:

• Mole Concept
• Atomic Structure
• Chemical Thermodynamics
• Chemical Equilibrium
• Chemical Kinetics
• Electrochemistry, etc.

The main topics to cover under Organic Chemistry are:

• Optical isomerism
• Conformation of acyclic systems
• Cyclic systems
• Stereochemistry
• Chemical reactions
• Identification of functional groups by chemical tests

Inorganic Chemistry

• S and P Blocks
• D Block
• Chemical Bonding and Shapes of Compounds
• Periodic Tables
• Bio-inorganic Chemistry
• Analytical Chemistry
• Isoptope etc.

These are some of the important topics to focus in Chemistry overall for IIT Jam preparation.

Good Luck!