NCERT Solutions for Class 12 Physics, Chapter 12 - Atoms

In this chapter, you’ll study about Atoms from the physics point of view. You have already studied about atoms in your previous classes. The first structural model of an atom (also known as the plum pudding model of the atom) was designed by J.J. Thomson in 1898. Then, Ernst Rutherford, a former research student of J. J. Thomson, introduced Rutherford’s planetary model of the atom (also called the nuclear model of the atom). Then, Bohr proposed three major postulates related to atoms. In this chapter, you’ll learn about alpha-particle scattering and Rutherford’s nuclear model of atom, alpha-particle trajectory, electron orbits, atomic spectra, spectral series, Bohr model of the hydrogen atom, the line spectra of the hydrogen atom, DE Broglie’s Explanation of Bohr’s second postulate of quantisation and then finally drawbacks of Bohr’s model.

Thus, an in-depth study of Class 12 Physics NCERT Solutions Chapter 12 will give you a good understanding of significant aspects of Atoms.

Let’s take a look at topics and sub-topics of Class 12 Physics Chapter 12– Atoms

12.1 Introduction

12.2 Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom

12.2.1 Alpha-particle trajectory

12.2.2 Electron orbits

12.3 Atomic Spectra

12.3.1 Spectral series

12.4 Bohr Model of the Hydrogen Atom

12.4.1 Energy levels

12.5 The Line Spectra of the Hydrogen Atom

12.6 DE Broglie’s Explanation of Bohr’s Second Postulate of Quantisation

In Class 12 Physics Chapter 12, you will learn – 

Section 12.2 – In this section, you will study about alpha-particle scattering and Rutherford’s nuclear model of the atom, alpha-particle trajectory and electron orbits. You’ll also come across the graphic representation of Geiger-Marsden scattering experiment and schematic arrangement of the Geiger-Marsden experiment.

Section 12.3 – In this section, you’ll acquire knowledge about atomic spectra and spectral series. You’ll study the diagram showing emission lines in the spectrum of hydrogen and Balmer series in the emission spectrum of hydrogen. You’ll also come across related terms like impact parameter, Balmer series, spectral series and Rydberg constant.

Section 12.4 – In this section, you’ll learn about the Bohr Model of the Hydrogen atom. You’ll study the three important postulates proposed by Bohr by combining classical and early quantum concepts. You’ll also learn about the energy levels of atoms in various situations.

Section 12.5 – In this section, you will study about the line Spectra of the Hydrogen atom and the third Postulate of Bohr’s model. You’ll also learn what are emission lines and the process of absorption.

Section 12.6 – In this section, you’ll learn DE Broglie’s Explanation of Bohr’s second postulate of Quantisation. You’ll also come across the diagram showing a standing wave on a circular orbit where four de Broglie wavelengths fit into the circumference of the orbit. Finally, you’ll study some limitations of Bohr’s model.

In this chapter, you are provided with several examples with their solutions for a clear understanding of Atoms. To know more about NCERT Solutions for Class 12 Physics Chapter 12, you should explore the exercises mentioned in this chapter. You can also download the NCERT Solutions for Class 12 Physics Chapter 12 PDF, solved by our science experts.