CIE A Level Chemistry復習筆記3.1.10 Structural Isomerism

Category: A-level課程, 教材筆記, 福利干貨 Date: 2022年8月12日下午3:31

Structural Isomerism: Chain, Position & Functional Group

Structural isomers?are compounds that have the same?molecular?formula but different?structural?formulae
- Eg. propene and cyclopropane

3.1-An-Introduction-to-AS-Level-Organic-Chemistry-Propene-and-Cyclopropane

Both propene and cyclopropane are made up of 3 carbon and 6 hydrogen atoms but the structure of the two molecules differs

There are three different types of structural isomerism:
- Chain?isomerism
- Positional?isomerism
- Functional?group isomerism

Chain isomerism

Chain isomerism?is when compounds have the same molecular formula, but their longest hydrocarbon chain is not the same
This is caused by branching
- Eg. pentane and 2,2-dimethylpropane

3.1-An-Introduction-to-AS-Level-Organic-Chemistry-Chain-Isomerism

Both compounds are made up of the same atoms however the longest carbon chain in pentane is 5 and in 2,2-dimethylpropane 3 (with two methyl branches)

Positional isomerism

Positional isomers?arise from differences in the position of a functional group in each isomer
- The functional group can be located on different carbons
- For example, butanol and 2-butanol

3.1-An-Introduction-to-AS-Level-Organic-Chemistry-Positional-Isomerism

Both compounds have an alcohol group and are made up of 4 carbon, 10 hydrogen and one oxygen atom however in butanol the functional group is located on the first carbon and in 2-butanol on the second carbon

Functional group isomerism

When different functional groups result in the same molecular formula,?functional group isomers?arise
The isomers have very different chemical properties as they have different functional groups
- For example, butanol and ethoxyethane

3.1-An-Introduction-to-AS-Level-Organic-Chemistry-Functional-Group-Isomerism