This is a complete A-level Chemistry lesson on cyclic compounds, functional-group priority and naming molecules with multiple functional groups

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This fully editable power point is designed for A-level Chemistry: 3.3.1 Introduction to Organic Chemistry 3.3.1.1 Nomenclature. It follows directly from Nomenclature Part 1, moving students from naming more complex branched organic compounds

The lesson uses a highly structured and carefully scaffolded approach to help students understand not only what a systematic name is, but why each part of the name has been selected.

Content covered

Students are supported to:

name and draw cyclic organic compounds;
recognise cycloalkanes and substituted cycloalkanes;
apply the cyclo- prefix correctly;
use the general formula Câ‚™Hâ‚‚â‚™ for cycloalkanes;
compare the general formula of cycloalkanes with that of alkenes;
number a ring to give substituents the lowest possible set of locants;
name substituted cyclic compounds such as dibromocycloalkanes;
identify aldehyde, ketone, carboxylic acid, nitrile and amine functional groups;
recall the correct structural representation and suffix for each functional group;
recognise functional groups in displayed, structural and skeletal formulae;
understand when the functional-group carbon is automatically carbon 1;
recognise why locant 1 is not normally written for aldehydes, carboxylic acids and nitriles;
identify the principal or highest-priority functional group;
select a parent structure containing the principal functional group;
number the parent structure to give the highest-priority functional group the lowest possible locant;
decide which functional group keeps the suffix;
convert lower-priority functional groups into prefixes;
name compounds containing two or more different functional groups;
use locants, prefixes, suffixes and punctuation accurately;
translate between systematic names and displayed, structural and skeletal formulae;
justify a systematic name using the parent structure, functional-group priority, numbering and substituent positions.
Functional-group priority

The lesson explicitly introduces and applies the following priority order:

carboxylic acid → nitrile → aldehyde → ketone → alcohol → amine → alkene → halogenoalkane

Students are taught that when a molecule contains two groups that could normally be expressed using suffixes, the higher-priority functional group retains the suffix, while the lower-priority functional group is expressed as a prefix. This is modelled through guided examples before students apply the rule independently.