Define organic compounds and hydrocarbons, and note conventional exclusions such as CO2 and carbonates.

Compare displayed, structural, and molecular formulae, and introduce structural isomerism.

List the shared traits of a homologous series: formula, functional group, chemistry, physical gradation, and CH2 steps.

Apply Cn patterns for alkanes, alkenes, alcohols, and carboxylic acids with worked examples.

Contrast single-bond alkanes with double-bond alkenes and how C=C can open to form new bonds.

Recap formulae language, general formulae, homologous series, and saturation tips for exam readiness.