4.1.1 Basic Concepts of Organic Chemistry

No. of carbons:

meth- 1, eth- 2, prop- 3, but- 4, pent- 5, hex- 6, hept- 7, oct- 8, non- 9, dec- 10

Nomenclature       IUPAC rules for naming organic compounds;

  • count carbons on longest carbon chain
  • use functional groups as prefixes or suffixes
  • other side chains are prefixes in alphabetical order, after no. carbon they are attached to
  • multiple identical side groups use di(2) tri(3) or tetra(4) before the name of their group.

General formula – the simplest algebraic formula of a member if a homologous series

Structural formula – written minimal detail that shows the arrangement of atoms in a molecule

Displayed formula – relative positioning of atoms and the bonds between them

Skeletal formula – the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups


Functional Groups

Homologous series – a series of organic compounds having the same functional group but with each successive member differing by CH2

Functional group – a group of atoms responsible for the characteristic reactions of a compound

Alkyl group – of formula CnH2n+1  (can be represented in diagrams as ‘R’)

Aliphatic – a compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings

Alicyclic – an aliphatic compound arranged in non-aromatic rings with or without side chains

Saturated – single carbon-carbon bonds only, no double bonds

Unsaturated – the presence of multiple carbon-carbon bonds (double or triple) and aromatic rings



Structural isomers – compounds with the same molecular formula but different structural formulae

Reaction Mechanisms

Covalent bond fissions 

homolytic fission – each bonding atom receiving one electron from the bonded pair, forming two radicals

Heterolytic fission – one bonded atom receiving both electrons from the bonded pair and the other receiving none

Radical – a species with an unpaired electron (dots • represent the electron in mechanisms)

Curly arrow – represents the movement of a lone pair of electrons in a mechanism (always starting from a bond, a lone pair of electrons or a negative charge)

Comments are closed.