Organic Chemistry – Some Basic Principles and Techniques - General Introduction

Carbon exhibits tetravalency and the unique property of catenation (self-linking), which allows it to form a vast variety of stable chains and rings. The ground state electronic configuration of carbon is $1s^2 2s^2 2p^2$.

Hybridization in organic compounds explains the geometry of molecules: $sp^3$ hybridization leads to tetrahedral geometry (bond angle $\approx 109.5^\circ$), $sp^2$ leads to trigonal planar geometry ($120^\circ$), and $sp$ leads to linear geometry ($180^\circ$).

A single covalent bond is always a $\sigma$ (sigma) bond. A double bond consists of one $\sigma$ and one $\pi$ (pi) bond. A triple bond consists of one $\sigma$ and two $\pi$ bonds.

Organic structures can be represented in multiple ways: Complete structural formulas (showing all bonds), Condensed structural formulas (omitting some or all bonds, e.g., $CH_3CH_2OH$), and Bond-line structural formulas (where lines represent $C-C$ bonds and vertices represent Carbon atoms).

Organic compounds are broadly classified into Acyclic (open chain) and Cyclic (closed chain) compounds. Cyclic compounds are further divided into Alicyclic and Aromatic compounds (like Benzene $C_6H_6$).

A functional group is an atom or a group of atoms joined in a specific manner which determines the chemical properties of the organic compound (e.g., $-OH$ for alcohols, $-CHO$ for aldehydes).

A Homologous series is a group of organic compounds having the same functional group and similar chemical properties, where successive members differ by a $-CH_2-$ unit and $14$ units of molecular mass.