Atomic Structure

Atomic structure mainly deals with how the structure of an atom evolved through time and the various aspects of each of these proposed atomic models. It is an easy scoring chapter with both problems and theory based questions being asked for exams. A good understand of sub topics in this chapter can easily fetch you full marks from this chapter.


Atomic structure has had a very low share in both JEE Mains and JEE Advanced exams with not more than 3 questions asked in one paper. Most questions were formula based numericals.

Important Topics

Most of the questions asked were numericals. A majority of them were based on Bohr's Model of Atom. Expressions for energy of electron(kinetic, potential and total), radius of electronic orbit, frequency/ wavelength of light during electronic trasitions, angular momentum of electron in an orbit and De Broglie wavelength of particles were frequently used to solve these numericals. Questions based on Photoelectric effect were also asked. Since most of these equations have the same terms but different exponential numbers, there is a greater risk of mixing them up. Make sure you know and use the right formula depending on the question. Its always better to know the expressions with a simplified value for all the constants involved as this reduces calculation time. Caution - Units of constant term should be checked. Some of these can also be found in "Modern Physics" chapter.

Theory questions were very few in number and mostly were based on Quantum Mechanical Model of an atom. Quantum numbers form an important part of questions asked. Student must know how to write the quantum numbers for any electron in a given atom. Understanding of Afbau Principle, Paulis Exclusion Principles and Hunds Rule of Maximum Multiplicity is essential to correctly predict the quantum number of an electron. The expressions for number of nodes (both radial and angular) should also be checked as a few questions were asked based on this.

At times questions were also asked from nuclear chemistry like identifying the mass and atomic number after !!alpha!!, !!beta!! or !!gamma!! emission. One or two questions were asked about binding energy and stability of nuclei.

Make sure that you go to the theory part from NCERT textbook as this would be sufficient enought to answer theory questions.

Again, its an easy chapter to score provided you're a bit careful. To find out if you have mastered this chapter, take our chapter wise test on Atomic Structure.

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