do people make notes on theory part of physics and chemistry?

Hi Sameer !!

Most of the students do make notes of the theory part. They also include the derivations in it.

If you think you can manage by going through the concepts in your books then it's up to you. However, you should know that making notes helps remember the concepts for long. Once you've gone through a particular concept, make notes in your own words. This will also help you gauge how much have you actually understood the concepts.