Candidates can check here the list of all the topics that are covered in NCERT class 12 solid state chapter.

• General characteristics of solid state
• Amorphous and crystalline solids
• Classification of crystalline solids
  • Molecular solids
  • Ionic solids
  • Metallic solids
  • Covalent or network solids
• Crystal lattices and unit cells
  • Primitive and centered unit cells
• Number of atoms in a unit cell
  • Primitive unit cubic cells
  • Body centered cubic unit cells
  • Face centered cubic unit cells
• Closed package structure
  • Formula of a Compound and Number of Voids Filled
• Packing efficiency
  • Packing Efficiency in hcp and ccp Structures
  • Efficiency of Packing in BodyCentred Cubic Structures
  • Packing Efficiency in Simple Cubic Lattice
• Calculations Involving Unit Cell Dimensions
• Imperfections in Solid
  • Types of Point Defects
• Electrical Properties
  • Conduction of Electricity in Metals
  • Conduction of Electricity in Semiconductors
• Magnetic Properties

• Class 12 Chemistry - Solid State

  The Solid State chapter is crucial for understanding the properties of solids and their classification based on structure, bonding, and defects. It is an important topic for JEE & NEET.

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  📌 Key Topics in Solid State

  1. Types of Solids

  • Crystalline Solids (Ordered arrangement, sharp melting point)
  • Amorphous Solids (Disordered arrangement, gradual softening)

  2. Classification of Crystalline Solids

  Type of Solid	Constituent Particles	Binding Forces	Example
  Ionic	Ions	Electrostatic	NaCl, KCl
  Covalent (Network)	Atoms	Covalent Bonds	Diamond, Graphite
  Metallic	Metal ions	Metallic Bonding	Fe, Cu
  Molecular	Molecules	Van der Waals Forces	Ice, CO₂

  3. Unit Cell and Crystal Lattice

  • Unit Cell: Smallest repeating unit of a crystal lattice.
  • Lattice Parameters: a, b, c (edge lengths) and α, β, γ (angles).
  • Types of Unit Cells:
    • Primitive (Simple Cubic)
    • Body-Centered Cubic (BCC)
    • Face-Centered Cubic (FCC)
    • Hexagonal Close-Packed (HCP)

  4. Packing Efficiency and Density

  • Packing efficiency: Percentage of total volume occupied by particles.
  • Density of Unit Cell: $$d = \frac{Z \times M}{a^3 \times N_A}$$ (Where Z = Number of atoms per unit cell, M = Molar mass, a = Edge length, $N_A$ = Avogadro's number)

  5. Defects in Solids

  • Point Defects:
    • Schottky Defect → Equal no. of cations & anions missing (NaCl).
    • Frenkel Defect → Ion displaced from normal position (AgCl).
  • Impurity Defects → Foreign atoms replace original ones (e.g., doping in semiconductors).

  6. Electrical and Magnetic Properties

  • Conductors, Semiconductors, and Insulators: Based on band theory.
  • Types of Magnetic Materials:
    • Paramagnetic (Fe³⁺, O₂)
    • Diamagnetic (NaCl, H₂O)
    • Ferromagnetic (Fe, Co, Ni)

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  🔥 Important Concepts & Formulae

  1. Number of Atoms in a Unit Cell

  Type of Unit Cell	Number of Atoms (Z)
  Simple Cubic (SC)	1
  Body-Centered Cubic (BCC)	2
  Face-Centered Cubic (FCC)	4
  Hexagonal Close Packed (HCP)	6

  2. Atomic Radius and Edge Length Relationships

  • Simple Cubic: $$a = 2r$$
  • BCC: $$a = \frac{4r}{\sqrt{3}}$$
  • FCC: $$a = \frac{4r}{\sqrt{2}}$$

  3. Packing Efficiency Formulae

  Lattice Type	Packing Efficiency (%)
  Simple Cubic	52.4%
  BCC	68%
  FCC & HCP	74%

  4. Density Formula

  $$d = \frac{Z \times M}{a^3 \times N_A}$$
  • $d$ = Density of unit cell
  • $Z$ = Number of atoms per unit cell
  • $M$ = Molar mass
  • $a$ = Edge length
  • $N_A$ = Avogadro’s number

  5. Coordination Number

  Crystal Structure	Coordination Number
  Simple Cubic	6
  BCC	8
  FCC & HCP	12

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  📌 Summary of Key Takeaways

  ✔ Solid State deals with structure, properties, and defects in solids.
  ✔ Types of solids depend on their bonding (Ionic, Covalent, Metallic, Molecular).
  ✔ Crystalline solids have a well-defined lattice structure.
  ✔ Packing efficiency, coordination number, and density are crucial for calculations.
  ✔ Schottky & Frenkel defects alter conductivity & density.
  ✔ Magnetic properties depend on electron alignment.

  Would you like numerical problems or concept clarifications? 😊

The Solid State chapter is an important chapter for the students because it forms a strong foundation for class XII students. It provides a glimpse of the scope of Chemistry to the students. The students can download here the Chemistry NCERT Class 12 PDF with solutions for free.

Download Here: NCERT Solution for Class XII Chemistry Solid State PDF