Hello

it is important for 12th 1st and 2 years as they might ask in long question, short question or MCQ. in JEE, it may or may not ask. t may ask like who invented and what was the primitive periodic table and who changed it. what elements were added later.

so it will be good if you remember it. They may ask as we don't know. it is unpredictable so we can't say that  JEE won't ask from this section. for default, you have to consider that they will ask from every corner of NCERT book. This why it is always advised to complete NCERT book line by line, along with examples, end chapter excersises.

did you know which is in left or right side of every page , they are also important. read summary of each chapters.

it is better to prepare well and leave on end left out. cover as much as you ca. learn, understand and remember it.

Hope it helps!