[2] Organic Definitons

Hydrocarbons

Hydrocarbons are compounds that contain only carbon and hydrogen atoms.

Nomenclature

Nomenclature is the set of rules that explain how organic compounds are named and how their formulae are represented.

Functional Group

A functional group is a group of atoms responsible for the characteristic reactions of a compound.

Homologous Series

A homologous series is a series of organic compounds with the same functional group, where each successive member differs by CH₂.

Alkyl Group

An alkyl group is a hydrocarbon chain with the general formula CₙH₂ₙ₊₁.

Aliphatic Compound

An aliphatic compound contains carbon and hydrogen joined together in straight chains, branched chains, or non-aromatic rings.

Alicyclic Compound

An alicyclic compound is an aliphatic compound arranged in non-aromatic rings, with or without side chains.

Aromatic Compound

An aromatic compound contains a fully conjugated ring.

Saturated Compound

A saturated compound contains single carbon-carbon bonds only.

Unsaturated Compound

An unsaturated compound contains multiple carbon-carbon bonds, including C=C, C≡C, and aromatic rings.

Isomerism

Isomerism occurs when molecules have the same molecular formula but a different arrangement of atoms.

Chain Isomers

Chain isomers have the same molecular formula but a different arrangement of the carbon skeleton.

Position Isomers

Position isomers have the functional group in a different position on the carbon chain.

Functional Group Isomers

Functional group isomers have the same molecular formula but different functional groups.

Curly Arrow

A curly arrow shows the movement of an electron pair during a reaction.

Fission

Fission is the breaking of a covalent bond.

Homolytic Fission

Homolytic fission occurs when each bonding atom receives one electron from the bonded pair, forming radicals.

Heterolytic Fission

Heterolytic fission occurs when one bonding atom receives both electrons from the bonded pair, forming ions.

Radical

A radical is a species with an unpaired electron.

Addition

An addition reaction occurs when reactants combine to form a single product.

Substitution

A substitution reaction occurs when one functional group is replaced by another functional group.

Oxidation

Oxidation is the loss of at least one electron.

Reduction

Reduction is the gain of at least one electron.

Polymerisation

Polymerisation is a reaction in which many small molecules (monomers) join together to form a polymer.

Elimination

An elimination reaction removes a small molecule from a larger molecule.

Empirical Formula

The empirical formula shows the simplest whole-number ratio of atoms of each element in a compound.

Molecular Formula

The molecular formula shows the actual number of atoms of each element in a compound.

General Formula

The general formula is the simplest algebraic formula representing members of a homologous series.

Structural Formula

The structural formula shows the arrangement of atoms in a molecule using minimal detail.

Displayed Formula

The displayed formula shows the relative positions of atoms and all bonds in a molecule.

Skeletal Formula

The skeletal formula is a simplified representation showing only the carbon skeleton, functional groups, and non-carbon atoms.