Structure and Bonding | Department of Chemistry

Structure and Bonding

Basic Chemistry 
Unit-1: Chemical periodicity 
Chemical periodicity 
Periodic table, group trends and periodic trends in physical properties. Classification of elements on the basis of electronic configuration. Modern IUPAC Periodic table. General characteristic of s, p, d and f block elements. Position of hydrogen and noble gases in the periodic table. Effective nuclear charges, screening effects, Slater’s rules, atomic radii, ionic radii (Pauling’s univalent), covalent radii. Ionization potential, electron affinity and electronegativity (Pauling’s, Mulliken’s and Allred-Rochow’s scales) and factors influencing these properties. Inert pair effect. Group trends and periodic trends in these properties in respect of s-, p- and d-block elements. 
Unit 2:Chemical Bonding and structure and acid-base reactions 
Ionic bonding: Size effects, radius ratio rules and their limitations. Packing of ions in crystals, lattice energy, Born-lande equation and its applications, Born-Haber cycle and its applications. Solvation energy, polarizing power and polarizability, ionic potential, Fazan’s rules. 
Covalent bonding: Lewis structures, formal charge. Valence Bond Theory, directional character of covalent bonds, hybridizations, equivalent and non-equivalent hybrid orbitals, Bent’s rule, VSEPR theory, Bonding, inductive effect, Hyperconjugation effect, mesomeric effect shapes of molecules and ions containing lone pairs and bond pairs (examples from main groups chemistry), Partial ionic Character of covalent bonds, bond moment, dipole moment and electronegativity differences. Concept of resonance, resonance energy, resonance structures 
Acid-Base reactions 
Acid-Base concept: Arrhenius concept, theory of solvent system (in H2O, NH3, SO2 and HF), Bronsted-Lowry’s concept, relative strength of acids, Pauling rules. Amphoterism. Lux-Flood concept, Lewis concept. Superacids, HSAB principle. Acid-base equilibria in aqueous solution and pH. Acid-base neutralisation curves; indicator, choice of indicators. 
Unit 3: An Introduction to Coordination Compounds 
Group theory, Bonding in coordination compounds, d-orbitals, t2g-eg splitting, structures of coordination complexes, octahedral and tetrahedral complexes, square planar complexes 
Unit 4: Basics of Organic Chemistry 
Homolytic and heterolytic bond fission. 
Hybridization, Bonding, inductive effect, Hyperconjugation effect, mesomeric effect, acidity and basicity of organic molecules, pKa,. Organic reactions; nucleophilic substitution, elimination, addition and electrophilic aromatic substitution reactions. Basic concept for characterization of organic molecules. 
Reaction intermediate: Carbocations, carbanions, free radicals,carbenes, Benzynes - their shape and stability. 
Electron displacements Inductive, electromeric, resonance, hyperconjugation. 
Electrophiles and nucleophiles. Nucleophilicity and Basicity 
Intermolecular forces of attraction: van der Waals forces, ion-dipole, dipole-dipole and hydrogen bonding. 
Aromaticity and Tautomerism 
Acidity/Basicity: Alkanes/Alkenes, Alcohols/Phenols/Carboxylic acids, Amines 
Molecular chirality and Isomerism 
Cycloalkanes (C3 to C8): Relative stability, Baeyer strain theory and Sachse Mohr theory. 
Structural- and Stereo-isomerism. 
Molecular representations: Newman, Sawhorse, Wedge & Dash, Fischer projections and their inter conversions. 
Conformations and Conformational analysis: Ethane, n-butane, ethane derivatives, 
cyclohexane, monosubstituted and disubstituted cyclohexanes and their relative stabilities. 
Geometrical isomerism in unsaturated and cyclic systems: cis–trans and, syn-anti isomerism, E/Z notations. Geometrical isomerism in dienes- Isolated and conjugated systems, determination of configurations. 
Chirality and optical isomerism: Configurational isomers. Molecules with one or two chiral centres- constitutionally symmetrical and unsymmetrical molecules; Enantiomers and Diastereomers. Optical activity, Disymmetry, Meso compounds, racemic modifications and methods of their resolution; stereochemical nomenclature: erythro/threo, D/L and R/S nomenclature in acyclic systems. 
Measurement of optical activity: specific rotation. 
Substitution reactions: 
Free radical- Halogenation, relative reactivity and selectivity. Allylic and benzylic bromination. 
Nucleophilic Subsititution (SN1, SN2, SN1′, SN2′ SNi) 
Electrophilic Substitution (SNAr, Addition Elimination vs. Elimination addition) 
Organometallic reagents

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