Topics
Some Basic Concepts of Chemistry
Introduction to Analytical Chemistry
- Introduction of Analytical Chemistry
- Analysis
- Mathematical Operation and Error Analysis
- Determination of Molecular Formula
- Chemical Reactions and Stoichiometric Calculations
- Limiting Reagent
- Concentration of a Solution
- Use of Graph in Analysis
Basic Analytical Techniques
- Introduction of Some Analytical Techniques
- Purification of Solids
- Crystallisation Method
- Fractional Crystallization
- Simple Distillation Method
- Solvent Extraction
- Chromatography Method
- Chromatography Method > Adsorption Chromatography
- Chromatography Method > Partition Chromatography
Structure of Atom
Chemical Bonding
- Concept of Chemical Bonding
- Kossel-lewis Approach to Chemical Bonding - Octet Rule
- Kossel and Lewis Approach to Chemical Bonding
- Formal Charge
- Limitations of the Octet Rule
- Valence Shell Electron Pair Repulsion (VSEPR) Theory
- Valence Bond Theory (VBT)
- Molecular Orbital Theory
- Parameters of Covalent Bond
- Dipole Moment
- Resonance
Redox Reactions
Modern Periodic Table
- Introduction of Periodic Table
- Structure of the Modern Periodic Table
- Periodic Table and Electronic Configuration
- Blockwise Characteristics of Elements
- Periodic Trends in Elemental Properties
Elements of Group 1 and 2
Elements of Group 13, 14 and 15
- Electronic Configuration of Elements of Groups 13, 14 and 15
- Trends in Atomic and Physical Properties of Elements of Groups 13, 14 and 15
- Chemical Properties of the Elements of the Groups 13,14 and 15
- Carbon: A Versatile Element
- Allotropes of Carbon > Diamond
- Molecular Structures of Some Important Compounds of the Group 13, 14 and 15 Elements
- Chemistry of Notable Compounds of Elements of Groups 13, 14 and 15
States of Matter
Adsorption and Colloids
Chemical Equilibrium
- Introduction of Chemical Equilibrium
- Equilibrium in Physical Processes
- Equilibrium in Chemical Processes - Dynamic Equilibrium
- Law of Mass Action and Equilibrium Constant
- Homogeneous Equilibria
- Characteristics of Equilibrium Constant
- Applications of Equilibrium Constants
- Le Chaterlier's Principle and Factors Altering the Composition of Equilibrium
- Industrial Application
Nuclear Chemistry and Radioactivity
- Introduction: Nuclear Chemistry is a Branch of Physical Chemistry
- Classification of Nuclides
- Nuclear Stability
- Radioactivity
- Radioactive Decays
- Modes of Decay
- Nuclear Reactions
- Applications of Radio Isotopes
Basic Principles of Organic Chemistry
- Organic Chemistry
- Structural Representation of Organic Molecules
- Classification of Organic Compounds
- Nomenclature
- Isomerism
- Theoretical Basis of Organic Reactions
Hydrocarbons
Chemistry in Everyday Life
Estimated time: 8 minutes
CBSE: Class 12
Maharashtra State Board: Class 12
Maharashtra State Board: Class 12
Key Points: Valence Shell Electron Pair Repulsion (VSEPR) Theory
- Proposed by Sidgwick and Powell (1940) and further developed by Nyholm and Gillespie.
- The geometry of a molecule depends on the total number of valence shell electron pairs (bond pairs + lone pairs) around the central atom.
- Electron pairs repel each other and arrange themselves as far apart as possible to minimise repulsion.
- Repulsion order:
lp–lp > lp–bp > bp–bp, and lone pairs occupy more space than bond pairs. - Presence of lone pairs reduces bond angle; if no lone pairs → molecular geometry = electron pair geometry.
VSEPR Geometry Table:
| Electron Pairs | Lone Pairs | Bonding Pairs | Electron Pair Geometry | Molecular Geometry | Examples |
|---|---|---|---|---|---|
| 2 | 0 | 2 | Linear | Linear | BeBr₂, CO₂ |
| 3 | 0 | 3 | Trigonal planar | Trigonal planar | BF₃, BCl₃, BH₃ |
| 4 | 0 | 4 | Tetrahedral | Tetrahedral | CH₄, NH₄⁺, SiCl₄ |
| 5 | 0 | 5 | Trigonal bipyramidal | Trigonal bipyramidal | PCl₅, SbF₅, AsF₅ |
| 6 | 0 | 6 | Octahedral | Octahedral | SF₆, TeF₆, SeF₆ |
| 3 | 1 | 2 | Trigonal planar | Bent | SO₂, O₃ |
| 4 | 1 | 3 | Tetrahedral | Trigonal pyramidal | NH₃, PCl₃ |
| 4 | 2 | 2 | Tetrahedral | Bent | H₂O, OF₂, H₂S, SCl₂ |
| 5 | 1 | 4 | Trigonal bipyramidal | See-saw | SF₄ |
| 5 | 2 | 3 | Trigonal bipyramidal | T-shaped | ClF₃, BrF₃, ICl₃ |
| 6 | 1 | 5 | Octahedral | Square pyramidal | BrF₅, IF₅ |
| 6 | 2 | 4 | Octahedral | Square planar | XeF₄ |
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Related QuestionsVIEW ALL [15]
Match List-I with List-II:
| List-I (Compound) |
List-II (Shape/Geometry) |
| A. NH3 | I. Trigonal pyramidal |
| B. BrF5 | II. Square planar |
| C. XeF4 | III. Octahedral |
| D. SF6 | IV. Square pyramidal |
Choose the correct answer from the options given below:
