Class 12th Chemistry Solid State NCERT Notes CBSE 2023
Launch Your Course Log in Sign up
Menu
Classes
Competitive Exam
Class Notes
Graduate Courses
Job Preparation
IIT-JEE/NEET
vidyakul X
Menu

Solid State Class 12 Notes

Solid State Class 12 Notes

Class 12 Chemistry Chapter 1 Solid State Notes – PDF Download

Chapter 1 The Solid State

It is an important chapter for CBSE 12th Board Students. Vidyakul's NCERT notes provide clear and precise answers to questions in the text, allowing students to understand the topic. 

This chapter discusses the intermolecular forces between atoms and the characteristics of the solids around us and attempts to clarify the concepts of the general properties of solids and the difference between amorphous and crystalline solids and helps students understand the nature of solids. binding force in matter.

CBSE CLASS 12th CHEMISTRY CHAPTER 1 NOTES

 

Points to Remember

Below we have provided some of the important points from the NCERT notes for Class 12 Chemistry Chapter 1:

  • A solid is a type of matter but has a definite shape and volume.

  • Furthermore, any deviation from a perfectly ordered arrangement of constituent particles is referred to as a defect or imperfection.

  • When the ratio of cations to anions remains constant, stoichiometric flaws occur. The two types of defects are Schottky and Frenkel.

  • Non-stoichiometric defects happen when the cation-anion ratio shifts as a result of the defect. There are two types of this defect: metal excess and metal deficiency.

  • Doping is also the addition of impurities to crystalline solids in order to alter their properties.

 

Topics and Sub-Topics 

Section

Topics

Description

Ex 1.1

General Characteristics of Solid State

Solids have definite volume, shape, and mass due to the short distance between the fixed position of particles and strong interactions between them.

1.1 Characteristics Properties of the Solid State

(i) They have definite mass, volume and shape.

(ii) Intermolecular distances are short.

(iii) Intermolecular forces are strong.

(iv) Their constituent particles (atoms, molecules or ions) have fixed positions and can only oscillate about their mean positions.

(v) They are incompressible and rigid.

 

Ex 1.2

Amorphous and Crystalline Solids

Solids can be classified as crystalline or amorphous on the basis of the nature of order present in the arrangement of their constituent particles. Amorphous solids behave like super cool liquids as the arrangement of constituent particles has short-range order, isotropic in nature and no sharp melting point. Crystalline solids have a characteristic shape, with the arrangement of constituent particles of long-range order, anisotropic in nature and a sharp melting point.

Ex 1.3

Classification of Crystalline Solids

The classification of crystalline solids is based on their property. The crystalline property depends on the nature of interactions between the constituent particles, and therefore these solids are divided into four different categories:

  • Ionic solids

  • Covalent or Network solids

  • Molecular solids

  • Metallic solids

 

Ex 1.3.1

Molecular Solids

 

Ex 1.3.2

Ionic Solids

 

Ex 1.3.3

Metallic Solids

 

Ex 1.3.4

Covalent or Network Solids

 

Ex 1.4

Crystal Lattices and Unit Cells

Unit Cell

The smallest repeating unit of the crystal lattice is the unit cell, the building block of a crystal.

Types Of Unit Cell

A lattice can be generated by repeating a small portion called the unit cell. Below are some of the different varieties of the unit cell:

  1. Primitive Cubic Unit Cell

  2. Body-centered Cubic Unit Cell

  3. Face centered cubic unit cell

 

Ex 1.4.1

Primitive and Centred Unit Cells

Primitive Cubic unit Cell

The primitive cubic unit cell has atoms only at its corner. Each atom at a corner is shared between eight adjacent unit cells four unit cells in the same layer and four-unit cells of the upper or lower layer. Therefore, only 1/8th of an atom actually belongs to a particular unit cell.

 

Ex 1.5

Number of Atoms in a Unit Cell

 

Ex 1.5.1

Primitive Cubic Unit Cell

Primitive Cubic unit Cell

The primitive cubic unit cell has atoms only at its corner. Each atom at a corner is shared between eight adjacent unit cells four unit cells in the same layer and four-unit cells of the upper or lower layer. Therefore, only 1/8th of an atom actually belongs to a particular unit cell.

 

 

Ex 1.5.2

Body-Centred Cubic Unit Cell

Number of Atoms in BCC Cell:

Thus, in a BCC cell, we have:

  • 8 corners × 1/8 per corner atom = 8 × 1/8 = 1 atom

  • 1 body center atom = 1 × 1 = 1 atom

Therefore, the total number of atoms present per unit cell = 2 atoms.

 

Ex 1.5.3

Face-Centred Cubic Unit Cell

Face-Centred Cubic unit Cell

A face-centred cubic unit cell contains atoms at all the corners and at the centre of all the faces of the cube. The atom present at the face-center is shared between 2 adjacent unit cells and only 1/2 of each atom belongs to an individual cell.

 

 

Ex 1.6

Close Packed Structures

a) Close Packing in One Dimension

In close packing one dimension, spheres are arranged in a row such that adjacent atoms are in contact with each other. Coordination number is defined as the no. of nearest neighbour particles. In case of one dimension close packing, the coordination number is equal to two.

(b) Close packing in Two Dimensions

In two-dimensional close packing, a row of closed packed spheres is stacked to obtain a two-dimensional pattern.

 

 

Ex 1.6.1

Formula of a Compound and Number of Voids Filled

Formula of a Compound and Number of Voids Filled

Voids literally mean gaps between the constituent particles. Voids in solid states mean the vacant space between the constituent particles in a closed packed structure.

 

Ex 1.7

Packing Efficiency

Packing Efficiency

Packing Efficiency is the percentage of total space filled by the particles.

 

Ex 1.7.1

Packing Efficiency in HCP and CCP Structures

Packing Efficiency in hcp and ccp Structures

Hexagonal close packing (hcp) and cubic close packing (ccp) have the same packing efficiency.

 

Ex 1.7.2

Efficiency of Packing in Body-Centred Cubic Structures

Efficiency Packing in Body-Centred Cubic Structures

In body centered cubic unit cell, one atom is located at body center apart from corners of the cube.

 

Ex 1.7.3

Packing Efficiency in Simple Cubic Lattice

Packing Efficiency in Simple Cubic Lattice

In the simple cubic unit cell, atoms are located at the corners of the cube.

 

Ex 1.8

Calculations Involving Unit Cell Dimensions

Calculations Involving Unit Cell Dimensions

The unit cell can be seen as a three-dimensional structure containing one or more atoms. We can determine the volume of this unit cell with the knowledge of the dimensions of the unit cell.

Mass of unit cell = number of atoms in unit cell × mass of each atom = z × m

Where, z = number of atoms in the unit cell, m = Mass of each atom

Mass of an atom can be given with the help of Avogadro number and molar mass as:

M/NA

Where M = molar mass

NA = Avogadro’s number

Volume of the unit cell, V = a3

=> Density of unit cell = mass of unit cell/ volume of the unit cell

=> Density of unit cell = m/V = z×ma/a3 = z×M/a3×NA

 

Ex 1.9

Imperfections in Solids

Imperfections in Solids

Point defects explain about the imperfections of solids along with the types of point defects. Point defects are accounted for when the crystallization process occurs at a very fast rate. These defects mainly happen due to deviation in the arrangement of constituting particles. The defects are of two types:

Point defects: Point defects are the irregularities or deviations from ideal arrangement around a point or an atom in a crystalline substance.

Line Defects: Line defects are the irregularities or deviations from an ideal arrangement in entire rows of lattice points. These irregularities are called crystal defects.

 

Ex 1.9.1

Types of Point Defects

Types of Point Defects

Point defects can be classified into three types:

1. Stoichiometric defect – In this kind of point defect, the ratio of positive and negative ions (Stoichiometric) and electrical neutrality of a solid is not disturbed. Sometimes it is also known as intrinsic or thermodynamic defects. Fundamentally, they are of two types: Vacancy defect and Interstitial defect

2. Frenkel defect – In ionic solids generally, the smaller ion (cation) moves out of its place and occupies an intermolecular space. In this case, a vacancy defect is created on its original position and the interstitial defect is experienced at its new position.

3. Schottky defect – This kind of vacancy defects is found in Ionic Solids. But in ionic compounds, we need to balance the electrical neutrality of the compound so an equal number of anions and cations will be missing from the compound. It reduces the density of the substance. In this, the size of cations and anions are of almost the same.

Ex 1.10

Electrical Properties

Electrical Properties

Solids can be classified into three types on the basis of their conductivities. They are:

(i) Conductors

(ii) Insulators

(iii) Semiconductors

 

Ex 1.10.1

Conduction of Electricity in Metals

 

Ex 1.10.2

Conduction of Electricity in Semiconductors

 

Ex 1.11

Magnetic Properties

Magnetic Properties

To study the magnetic properties of Magnetic Materials, the material is usually placed in a uniform magnetic field and then the magnetic field is varied. There are five major kinds of magnetic behaviour:

(i) Diamagnetic materials

(ii) Paramagnetic materials

(iii) Ferromagnetic materials

(iv) Antiferromagnetic materials

(v) Ferrimagnetic materials

 

 


The topics and sub-topics covered in Solid State Class 12 Notes are:

1.1 General Characteristics of Solid State

1.2 Amorphous and Crystalline Solids

1.3 Classification of Crystalline Solids

1.3.1 Molecular Solids

1.3.2 Ionic Solids

1.3.3 Metallic Solids

1.3.4 Covalent or Network Solids

1.4 Crystal Lattices and Unit Cells

1.4.1 Primitive and Centred Unit Cells

1.5 Number of Atoms in a Unit Cell

1.5.1 Primitive Cubic Unit Cell

1.5.2 Body-Centred Cubic Unit Cell

1.5.3 Face-Centred Cubic Unit Cell

1.6 Close Packed Structures

1.6.1 Formula of a Compound and Number of Voids Filled

1.7 Packing Efficiency

1.7.1 Packing Efficiency in hcp and ccp Structures

1.7.2 Efficiency of Packing in Body-Centred Cubic Structures

1.7.3 Packing Efficiency in Simple Cubic Lattice

1.8 Calculations Involving Unit Cell Dimensions

1.9 Imperfections in Solids

1.9.1 Types of Point Defects

1.10 Electrical Properties

1.10.1 Conduction of Electricity in Metals

1.10.2 Conduction of Electricity in Semiconductors

1.11 Magnetic Properties.

​Download this solution for FREE Download This PDF 

Download Vidyakul App for more Important notes, PDF's and Free video lectures.

Solid State Notes Class 12 Chemistry Notes Part - 2

Solid State Notes Class 12 Chemistry Notes Part - 3

Solid State Notes Class 12 Chemistry Notes Part - 4

Solid State Notes Class 12 Chemistry Notes Part - 5

Solid State Notes Class 12 Chemistry Notes Part - 6

Solid State Notes Class 12 Chemistry Notes Part - 7

Solid State Notes Class 12 Chemistry Notes Part - 8

Solid State Notes Class 12 Chemistry Notes Part - 9

Solid State Notes Class 12 Chemistry Notes Part - 10

Solid State Notes Class 12 Chemistry Notes Part - 11

Solid State Notes Class 12 Chemistry Notes Part - 12

Solid State Notes Class 12 Chemistry Notes Part - 13

Solid State Notes Class 12 Chemistry Notes Part - 14

Few Important Questions

  • What are ‘Crystalline solids’?

Crystalline solids are solids whose constituents are arranged in a highly ordered microscopic structure forming a crystal lattice.

  • What is a ‘Unit cell’?

A unit cell is the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire crystal.

  • What is ‘Packing Efficiency’?

The packing efficiency is the fraction of the crystal/unit cell actually occupied by the atoms.


Practice Questions

  1. Explain the term coordination number.

  2. Distinguish between Cubic close-packing and Hexagonal close-packing.

  3. Explain why Ionic solids are brittle and hard.

  4. Distinguish between a semiconductor and a conductor.

  5. Explain Paramagnetism with a suitable example.

Important Links: