Assignment 14C: Designing molecules
Distinction Version
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, STRUCTURAL ISOMERISMS:
The molecules which possess similar molecular formula but unsimilar atomic
arrangement are known as isomers. Structural isomers are made when
molecules having the same number of atoms in them possess completely
different arrangements. It is the most radical kind of isomerism. Types of
structural isomers:
Structural isomerism is further classified into three main types which are
explained below:
• Chain isomers:
When two molecules having similar molecular formula exhibit different main
chain, they give arise to chain isomerism. In simple words, chain isomers are
made because of the different orders of carbon chain in a compound. For
example, an alkane known as butane having molecular formula of C4H10 has
can have two possible chain isomers. One is n-butane and the other one is
2methyl propane. In n-butane, four carbon atoms are attached to hydrogen
atoms by single covalent bonding in a straight carbon chain. Whereas in 2methyl
propane one carbon atom is positioned at carbon 2 in a parent carbon chain of
3 atoms.