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 → P-block elements ↓


Group 18 Elements


The p-block elements include a fascinating group of elements known as the noble gases. These are found in group 18 of the periodic table. The noble gases are a distinctive group of elements that exhibit unique characteristics due to their full valence electron shell. This article explores these elements, their properties, and their applications.

Introduction to noble gases

The noble gases, also called inert gases, consist of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radioactive radon (Rn). These gases are characterized by their lack of chemical reactivity under standard conditions, due to having a complete octet of electrons in their outer shell.

Properties of noble gases

Physical properties

The noble gases are colourless, odourless and tasteless under standard conditions. They exist as monatomic gases and have relatively low boiling and melting points. The lack of colour, taste and odour can be highlighted using a simple atomic model:

This SVG shows electron shells without special electrons, symbolizing the complete outermost shell of the noble gases.

Chemical properties

The noble gases have a full valence shell represented as 1s^2 for helium and ns^2np^6 for other elements, often represented as octets. This full shell makes these gases highly stable and chemically inert or non-reactive.

Helium: 1s²
Neon: [He]2s²2p⁶
Argon: [Ne]3s²3p⁶
Krypton: [Ar]3d¹⁰4s²4p⁶
Xenon: [Kr]4d¹⁰5s²5p⁶
Radon: [Xe]4f¹⁴5d¹⁰6s²6p⁶

Presence of noble gases

There are several sources of noble gases:

  • Helium: Found in natural gas reserves produced by the radioactive decay of heavy elements in the Earth's crust.
  • Neon, Argon, Krypton and Xenon: These gases are obtained by fractional distillation of liquid air.
  • Radon: Naturally occurring radon is a decay product of radium, found in trace amounts in the atmosphere.

Uses of noble gases

The inert nature of noble gases makes them suitable for various applications in different fields.

Helium (He)

Helium is lighter than air and non-flammable, making it ideal for use in airplanes and balloons.

He
  • Cryogenics: Helium's low boiling point makes it usable as a coolant for superconductors and cryogenics.
  • Pressurization and purification: Due to its inertness, helium is used in a variety of gas pressure applications.

Neon (Ne)

Neon's ability to emit light when electrified makes its use in neon signs possible.

by
  • Neon lighting: Neon lights are used to illuminate signs, especially in advertising.
  • High-voltage indicators: The glow of neon is useful in high-voltage applications.

Argon (Ar)

Argon is often used in situations where non-reactivity is required.

AR
  • Welding: Argon arc creates a protective atmosphere for welding and cutting.
  • Preservation: It is used in the preservation of incandescent and fluorescent light bulbs and historical documents.

Krypton (Kr)

Krypton's unique light emission is used in a variety of lighting solutions.

Sl
  • Lighting: Krypton is used in high-performance lighting, such as airport runway lights.
  • Photography: Used in some photographic flashes for high-speed photography.

Xenon (Xe)

Xenon is used in applications requiring high-power lamps.

Ze
  • Flash lamps: Xenon is used in flash lamps for high intensity discharge lamps.
  • Medical imaging: It is used in medical imaging, especially computed tomography (CT) scans.

Radon (Rn)

Although radon is radioactive and has limited uses, it is especially used in geological studies.

R N
  • Geological studies: Radon concentration measurements are used in earthquake prediction studies, tracking emissions in the Earth's crust.
  • Cancer treatment: Radon has been used in radiotherapy to treat cancer, although its use is now limited due to the health risks.

Closing thoughts

With their stable electron configurations, the noble gases hold a unique position in chemistry. They bring many practical applications because of their inertness and ability to emit light under certain conditions. While many new techniques continue to take advantage of the properties of the noble gases, special care must be taken in handling certain gases, such as radon, because of their radioactive nature. An understanding of the noble gases provides a gateway to appreciating the balance and diversity of the periodic table, which is a vital tool in the study and application of chemistry.


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Group 17 Elements (Halogens and their Compounds)
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Properties and Trends in p-Block Elements

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Group 18 Elements

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