Ans: The NCERT Class 11 Chapter 2, Structure of Atom, belongs to unit 2 of the NCERT syllabus. For the class 11 year-end exam, unit 1 and unit 2, when combined, carries a massive weightage of 11 marks. Through this chapter, students learn about the subatomic particles, namely, electrons, protons, and neutrons, their discoveries, and their characteristics.