Grade 12
  1. Solid state  1.1. Classification of solids  1.2. Crystal Lattice and Unit Cell  1.3. Packing Efficiency  1.4. Density of unit cell  1.5. Imperfections in solids (point and line defects)  1.6. Electrical Properties of Solids (Conductors, Insulators and Semiconductors)  1.7. Magnetic Properties of Solids (Diamagnetic, Paramagnetic and Ferromagnetic Materials)
  2. Solution  2.1. Types of Solutions (Homogeneous and Heterogeneous)  2.2. Expressing concentration of solutions (mass %, volume %, molarity, molality, normality, mole fraction)  2.3. Solubility of solids and gases in liquids (Henry's law)  2.4. Raoult's Law and Ideal and Non-Ideal Solutions  2.5. Syndrome properties  2.6. Abnormal molar mass and Van't Hoff factor
  3. Electrochemistry  3.1. Electrochemical cells (galvanic and electrolytic cells)  3.2. Galvanic cell and EMF of the cell  3.3. Standard electrode potential and electrochemical series  3.4. Nernst equation and its applications  3.5. Conductivity and electrolytic cells (specific, molar and equivalent conductivity)  3.6. Kohlrausch's law and its applications  3.7. Batteries (primary and secondary cells)  3.8. Corrosion and its prevention
  4. Chemical kinetics  4.1. Rate of chemical reaction  4.2. Factors affecting the reaction rate (concentration, temperature, catalyst, surface area)  4.3. Order and molecularity of the reaction  4.4. Integrated Rate Equations (Zero, First and Second Order)  4.5. Half-life of a reaction  4.6. Collision theory and activation energy  4.7. Arrhenius equation and its applications
  5. Surface chemistry  5.1. Adsorption and its types (Physicosorption and Chemisorption)  5.2. Catalysis and its types (homogeneous and heterogeneous)  5.3. Colloids and their properties (Tyndall effect, Brownian motion, coagulation)  5.4. Emulsions and gels  5.5. Applications of Colloids
  6. General principles and processes of separation of elements  6.1. Presence of metals and minerals  6.2. Concentration of ores (gravity separation, froth flotation, magnetic separation)  6.3. Extraction of raw metals (roasting, calcination, reduction)  6.4. Thermodynamic and electrochemical principles of metallurgy  6.5. Refining of metals
  7. P-block elements  7.1. Group 15 elements (nitrogen and phosphorus)  7.2. Group 16 Elements (Oxygen, Sulphur and their Compounds)  7.3. Group 17 Elements (Halogens and their Compounds)  7.4. Group 18 Elements  7.5. Properties and Trends in p-Block Elements  7.6. Important compounds of p-block elements (ammonia, phosphine, sulphuric acid, hydrochloric acid)  7.7. Interhalogen compounds and their applications
  8. d-block and f-block elements  8.1. General Properties of Transition Metals  8.2. Properties of Inner Transition Metals (Lanthanoids and Actinoids)  8.3. Lanthanoid and actinoid contractions  8.4. Coordination Chemistry of d-Block Elements
  9. Coordination compounds  9.1. Werner's theory and modern concepts  9.2. Coordination number and type of ligand  9.3. Nomenclature of Coordination Compounds  9.4. Isomerism (geometrical and optical) in coordination compounds  9.5. Bonding in Coordination Compounds (Valence Bond Theory and Crystal Field Theory)  9.6. Stability and applications of coordination compounds in medicine and industry
  10. Haloalkanes and haloarenes  10.1. Classification and nomenclature of haloalkanes and haloarenes  10.2. Physical and Chemical Properties of Haloalkanes and Haloarenes  10.3. Mechanism of Nucleophilic Substitution Reactions (SN1 and SN2)  10.4. Uses and environmental effects (ozone depletion, CFCs)
  11. Alcohol, phenol and ether  11.1. Structure and classification of alcohols, phenols and ethers  11.2. Preparation and properties of alcohols  11.3. Preparation and properties of phenol  11.4. Preparation and properties of ethers  11.5. Chemical Reactions and Uses
  12. Aldehydes, ketones and carboxylic acids  12.1. Structure and nomenclature in aldehydes, ketones and carboxylic acids  12.2. Preparation and properties of aldehydes and ketones  12.3. Chemical reactions in aldehydes, ketones and carboxylic acids (nucleophilic addition, oxidation and reduction)  12.4. Preparation and Properties of Carboxylic Acids  12.5. Chemical Reactions and Uses of Carboxylic Acids
  13. Nitrogen-containing organic compounds  13.1. Amines (classification, structure, basicity)  13.2. Preparation and properties of amines  13.3. Reactions of Amines (Diazotization, Carbylamine Reaction)  13.4. Diazonium salts and their applications in paint industry
  14.1. Carbohydrates (classification and properties)  14.2. Proteins (Structure and Function)  14.3. Enzymes (Mechanism and Function)  14.4. Nucleic acids (DNA and RNA)  14.5. Vitamins and hormones
  15. Polymer  15.1. Classification of Polymers (Addition, Condensation, Copolymers)  15.2. Types of polymerization (free radical, ionic, condensation)  15.3. Important Polymers and Their Uses  15.4. Biodegradable and non-biodegradable polymers
  16. Chemistry in Everyday Life  16.1. Drugs and their classification (analgesics, antipyretics, antibiotics, antacids)  16.2. Chemicals in food and cosmetics (preservatives, artificial sweeteners, antioxidants)  16.3. Cleaning agents and detergents (soaps, synthetic detergents, surfactants)  16.4. Environmental Chemistry (Pollution, Green Chemistry, Sustainable Chemistry)

Grade 12 ↓


Solid state


The study of the solid state is an important component of chemistry and materials science. Understanding the solid state is fundamental as it forms the basis for explaining the properties and behaviour of many materials we encounter in daily life. In this lesson, we will delve deeper into the nature of solids, their different types, structures, and properties. We will explore the microscopic and macroscopic concepts that define the solid state, ensuring that the explanations are straightforward and easy to understand.

What is solid?

Solids are one of the fundamental states of matter, along with liquids and gases. In solids, particles are closely packed together, either in a regular pattern or irregularly, and are in a fixed position relative to each other. This structure gives solids their characteristic shape and volume. Unlike liquids and gases, solids do not conform to the shape of their container.

Types of solids

Solids are generally classified into two primary types based on their internal structure:

1. Crystalline solid

Crystalline solids have a highly ordered structure, where the particles (atoms, molecules, or ions) form a repeating pattern. This ordered arrangement extends over long distances within the solid, giving it distinct geometric shapes. Common examples of crystalline solids include NaCl (table salt), diamond, and quartz.

Visual example: structure of NaCl

2. Amorphous solid

Amorphous solids do not have a well-defined long-range order. The arrangement of particles in these solids is random. Amorphous solids include materials such as glass, plastics, and gels. Although they maintain a rigid structure, their internal patterns are disordered.

Comparison example

Consider comparing the clarity and structure of a window made of glass (an amorphous solid) to a diamond (a crystalline solid). Glass appears clear and smooth because of its irregular internal structure, while a diamond's reflective facets and durable shape are due to its ordered internal lattice.

Crystal lattices and unit cells

Crystalline solids consist of repeating units called unit cells. These unit cells are arranged together in three-dimensional space to form a crystal lattice. The unit cell is the smallest structural component that forms the entire lattice through repeated translations along its axis.

Visual example: simple cubic unit cell

Types of crystal systems

Crystals can be classified based on their shape and the angles between their faces. There are seven primary crystal systems:

  • Cube
  • Square
  • Orthorhombic
  • Hexagonal
  • Tikona
  • Monoclinic
  • Triclinic

Properties of solids

The properties of solids are directly related to their structural arrangement and the type of particles they contain. Here are some important properties to consider:

Mechanical properties

Solids are characterized by their resistance to deformation and their ability to bear loads:

  • Hardness: The resistance of a solid object to scratching or abrasion.
  • Elasticity: The ability of a solid object to return to its original shape after deformation.
  • Brittleness: The tendency of a solid object to break or shatter without significant deformation.

Optical properties

These are determined by how a solid object interacts with light:

  • Transparency: A measure of the ability of a solid object to allow light to pass through it.
  • Refractive index: A measure of how much light bends when entering a solid.

Electrical properties

The electrical properties depend on the ability of electrons to move within a solid:

  • Conductors: Solid materials that allow the free movement of electrons (e.g., metals).
  • Insulators: Solid materials that impede the flow of electrons (e.g., rubber).
  • Semiconductors: Solid materials that have conductivity between conductors and insulators (e.g., silicon).

Bonding in solids

The types of bonds that hold a solid together define its characteristics:

  • Ionic solids: contain ionic bonds formed between positively and negatively charged ions, such as NaCl.
  • Covalent solid: Atoms are joined by covalent bonds, e.g., diamond.
  • Metallic solids: Positive metal ions surrounded by a sea of free electrons, e.g., copper.

Visual example: metallic bond

Defects in solids

Real solids contain imperfections called defects, which can significantly affect their properties:

  • Point defects: occur at a single lattice point, such as vacancies where atoms are missing.
  • Line defects: Dislocations, which are defects along a whole chain of atoms in a lattice.
  • Surface defects: These defects occur on surfaces, such as at grain boundaries.

Conclusion

The solid state involves a variety of structures and properties that are shaped by the arrangement and bonding of constituent particles. Understanding these principles is fundamental in materials science and is important for developing new materials with desired properties. By exploring the types, structures, and interactions of solids, we gain insight into their applications and potential in a variety of fields such as engineering, electronics, and everyday applications.


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Solid state

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