Study Chemistry notes on Isomerism for Secondary. Useful for revision, homework, and exam preparation in Zimbabwe.
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Isomerism
It is possible for organic molecules with the same molecular formula to have different structures
Definition- Structural isomers: same molecular formula different structures (or structural formulae)
There are three types of structural isomerism
-Chain isomerism
-Position isomerism
-Functional group isomerism
Chain isomerism: Compounds with the same molecular formula but different structures of the carbon skeleton
These isomers arise because of the carbon chains can be branched. For example, there are two isomers of butane, $\mathrm{C}_{4} \mathrm{H}_{10}$. In one of them, the carbon atoms lie in a "straight chain" whereas in the other the chain is branched
butane
methyl propane
There are three isomers of pentane $\mathrm{C}_{5} \mathrm{H}_{12}$
pentane
2-methylbutane
2,2-dimethylpropane
False isomers
Do not draw "false" isomers which are just twisted versions of the original molecule. Twisting the molecule into a different shape does not make a different isomer. Isomers are only formed if a bond would have to be broken and reassembled into the different structure
These are all exactly the same compound.
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