Atoms and Nuclei: Key Concepts, Formulas & Quick Revision

This is one of the important chapters for JEE Main Exams, and you can expect a minimum of 3 questions from this chapter. Have a look at the number of questions asked from the Atoms and Nuclei chapter in the past five years of the JEE Main exam. You will get an idea of the importance of Atoms and Nuclei in JEE Main by looking at the table below.

It is important to note that the JEE Main syllabus and question paper pattern are subject to change every year, so the number of questions asked from this chapter may vary in future exams. However, it is still a very important chapter to study for the JEE Main Physics section, as it covers a wide range of topics that are likely to be tested.

Take advantage of the opportunity to boost your preparation with our Atoms and Nuclei Notes. These notes cover the entire JEE Main Physics syllabus; you can download them for FREE.

Atoms and Nuclei JEE Main 2026: Important Topics

Here are a few important topics students should consider when learning the Atoms and Nuclei chapter. These subjects are selected from previous years' JEE Main exams. Therefore, before you get the Revision notes, you can review this list of significant topics from Atoms and Nuclei.

• Bohr's Model of the Atom

• Hydrogen Spectrum

• Quantum Numbers

• Electronic Configuration

• Pauli Exclusion Principle

• Aufbau Principle and Hund's Rule

• Isotopes and Isobars

• Radioactivity

• Nuclear Reactions

• Binding Energy

• Mass Defect

• Nuclear Models

• Radioactive Decay Law

• Nuclear Reactors

Power of Equations: How Formulas Amplify Revision Notes Learning

Equations aren't just symbols; They are your key to solving problems in physics. By grasping formulas, you'll tackle complex concepts effortlessly and improves your confidence. Dive into the world of equations along with JEE Main Physics Revision notes and amplify your study sessions. Explore our JEE Physics formula pages to prepare for JEE Main today!

Below are the few Important Formuals from this chapter for your reference.

1. Mass-Energy Equivalence:  

$E = mc^2 $

where E is energy, m is mass, and c is the speed of light.

2. Radius of Nucleus:  

$R = R_0 A^{1/3} $

where R is the nuclear radius, $R_0 $ is a constant $(1.2 \times 10^{-15}$ m), and A is the mass number.

3. Binding Energy per Nucleon:  

$BE = \frac{E_{\text{binding}}}{A} $

where BE is the binding energy per nucleon, $E_{\text{binding}} $is the total binding energy, and A is the mass number.

4. Nuclear Decay Law (Radioactive Decay):  

$N = N_0 e^{-\lambda t} $

where N is the number of undecayed nuclei at time t, $N_0 $ is the initial number of nuclei, and $\lambda $ is the decay constant.

5. Half-Life Formula:  

$T_{1/2} = \frac{\ln(2)}{\lambda} $

where $T_{1/2} $is the half-life, and $\lambda $is the decay constant.

6. Activity of a Radioactive Sample:

$A = \lambda N $

where A is the activity, $\lambda $ is the decay constant, and N is the number of undecayed nuclei.

Why are Notes of Atoms and Nuclei Important for JEE Main 2026?

Mastering Notes of Atoms and Nuclei is vital for JEE Main 2026 as it forms the foundation for understanding fundamental concepts in physics and ensures success in the exam. Let’s explore how Vedantu can be your perfect guide for JEE Main preparation:

1. Crucial for JEE Main Success: Mastery of the Atoms and Nuclei chapter is crucial for success in JEE Main, where a deep understanding of atomic and nuclear concepts is tested extensively.

2. Confident Problem Solving: Vedantu aids students in mastering fundamental concepts of Atoms and Nuclei for JEE Main, empowering them to confidently solve complex problems related to atomic structure and nuclear processes.

3. Encouragement to Explore Further: Vedantu's Atoms and Nuclei resources not only cover the essentials for JEE Main but also encourage students to explore additional problems and practice extensively, with these sample papers promoting a comprehensive understanding.

4. Embrace Mastery for Rewarding Feeling: Students who embrace mastery of the Atoms and Nuclei chapter with Vedantu experience a rewarding feeling, setting themselves on a path to success in JEE Main.

5. Pivotal Notes for JEE Main 2026: Vedantu provides pivotal notes on Atoms and Nuclei, serving as a foundation for understanding complex topics related to atomic structure, nuclear processes, and radioactivity, crucial for JEE Main 2026.

6. Confidence Building for Candidates: With Vedantu's guidance, candidates can confidently tackle main questions related to atomic and nuclear phenomena in the JEE main exam, ensuring a solid grasp of fundamental principles for success in 2026.

Here are the major features of the chapter Atoms and Nuclei:

• The chapter covers the structure of the atom, including the subatomic particles, the nucleus, and the electron cloud.

• It also discusses nuclear physics, which is the study of the nucleus of the atom. This includes topics such as nuclear reactions, radioactivity, and nuclear fusion.

• The chapter also covers the binding energy of the nucleus, which is the energy that holds the nucleus together.

Here are some of the specific topics that are covered in the chapter:

• Rutherford's gold foil experiment

• Bohr's model of the atom

• Atomic spectra

• Isotopes, isobars, and isotones

• Radioactivity

• Nuclear fission

• Nuclear fusion

• Binding energy

These topics are important for JEE Main aspirants because they are likely to be tested in the exam. In addition, they provide a foundation for understanding more advanced topics in physics, such as nuclear physics and particle physics.

Benefits of Learning Atoms and Nuclei for JEE Mains with Vedantu’s Notes 

• Vedantu’s notes cover key topics in Atoms and Nuclei, like atomic models, nuclear reactions, and radioactivity, making complex ideas easier to understand.

• Important formulas and tips in these notes help students solve various types of JEE problems effectively, saving time during revision.

• Created by subject experts, Vedantu's notes ensure accurate and relevant content that aligns perfectly with the JEE Mains syllabus.

• Vedantu’s FREE downloadable PDF format allows students to study and review Atoms and Nuclei on the go, making preparation flexible.

• With detailed explanations and examples, these notes build strong problem-solving skills for questions on atomic structure, nuclear forces, and decay.

• Learning with Vedantu’s structured notes helps students gain confidence in their understanding of Atoms and Nuclei, ensuring they’re well-prepared for exam day.

Here are some tips for studying the chapter Atoms and Nuclei:

• Start by understanding the basic concepts of atomic structure and nuclear physics.

• Then, focus on the specific topics that are likely to be tested in the exam.

• Practice solving problems related to these topics.

• Use online resources, such as Vedantu, to get help if you are stuck.

By following these tips, you can be sure to master the material in the chapter Atoms and Nuclei and be well-prepared for the JEE Main exam.

Check Other Important Links for JEE Main 2026 Atoms and Nuclei 

Explore additional resources beyond JEE Main 2026 Atoms and Nuclei notes. Check out these other useful links that provide access to learning materials, practice papers, mock tests, and valuable insights. Enhance your preparation, overcome difficulties, and welcome achievement with these resources designed specifically for JEE Main 2026.

JEE 2026 Physics Notes: Get Chapter-wise Links Here

Access organized JEE 2026 Physics Notes with convenient chapter-wise links. Dive into essential topics, understand key concepts, and prepare effectively for your exams. Get the edge you need with these focused notes.

Download Subject-wise Notes for JEE Main 

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