Structure of Atom Weightage in JEE Mains 2025

Structure of Atom Weightage in JEE Mains 2025: The Chemistry chapters occupy eminent significance in the JEE Main entrance exam. JEE Main 2025 aspirants are required to prepare for all the subjects in the appropriate manner. JEE Main 2025 candidates must be aware of the chapter-wise weightage for each subject for effective preparation. The Structure of Atom Weightage in JEE Mains 2025 is estimated to be 6.6.% of the total Chemistry weightage. Based on the previous year's analysis, students can expect around 2 questions from this topic. Some topics with high weightage in the JEE Main Chemistry syllabus are Structure of Atoms, Chemical Bonding, Transition Elements & Coordination Chemistry, and Thermodynamics & Gaseous State amongst others. The Structure of Atom chapter is important as it deals with the physical and chemical properties of various atoms and molecules. Candidates can check the weightage and chapters in the Structure of Atom in the article.

Also Read: JEE Main 2025 Exam Pattern

An Overview of Structure of Atom

The Structure of Atom section of the JEE Main 205 Chemistry Syllabus is a fundamental chapter dealing with the composition, behaviour and properties of atoms which act as the building blocks of matter. The key concepts covered in Structure of Atom have been discussed below.

• Subatomic Particles - These comprise electrons which are negatively charged particles discovered by J.J. Thomson via cathode ray experiments, protons which are positively charged particles discovered by Goldstein and neutrons which are neutral particles discovered by James Chadwick.

• Atomic Models - Atomic models comprise various models which have been discussed below.

1. Dalton's Atomic Theory - It states that atoms are indivisible and indestructible.
2. Thomson's Model (Plum Pudding Model) - It describes an atom as a sphere of positive charge with electrons embedded in it.
3. Rutherford’s Nuclear Model - It states that an atom has a dense, positively charged nucleus surrounded by electrons in empty space.
4. Bohr’s Model - It states that electrons revolve in specific orbits with quantized energy.
5. Quantum Mechanical Model - It describes electrons as wave functions with probabilistic distributions around the nucleus.

• Quantum Mechanics - They comprise;

1. Dual Nature of Matter and Radiation - It states that particles such as electrons exhibit both wave and particle properties.
2. Heisenberg’s Uncertainty Principle: It states that it is impossible to simultaneously measure the position and momentum of a particle with absolute accuracy.
3. Quantum Numbers- Principal (n) represents the shell, azimuthal (l) signifies the subshell or orbital shape, magnetic (m) signifies the orientation of orbitals and spin (s) represents the electron's spin direction.

• Hydrogen Spectrum - It comprises;

1. Line Spectrum: These are emission lines produced when electrons transition between energy levels.

2. Balmer, Lyman, Paschen, Brackett, and Pfund Series: They represent transitions in different spectral regions.

Also Read: JEE Main Previous Year Question Paper

Structure of Atom Weightage in JEE Mains 2025

Aspirants preparing for the JEE Main 2025 exam can check the Structure of Atom weightage in JEE Mains 2025 in the following table.

JEE Main Structure of Atom Weightage 2024

Check the JEE Main 2024 Weightage of the Structure of the Atom in the following table

Structure of Atom Weightage in JEE Main 2023

Given below is the JEE Main Structure of Atom Weightage 2023.

JEE Main Structure of Atom Weightage 2022

Students can examine the JEE Main structure of atom weightage 2022 below.

Structure of Atom Weightage in JEE Main 2021

Check the weightage of the Structure of the Atom for JEE Main 2021 in the following table.

JEE Main Structure of Atom Weightage Chemistry (2020-2019)

Below is the weightage for the structure of atoms as covered in the JEE Main examinations for the years 2020 and 2019.