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SAI International School

Class-X
Subject_ Chemistry
Topic- Carbon & it's Compounds

Subtopic-Isomerism
Lesson Notes

 Isomerism-
The phenomenon of the existence of different organic compounds having same
molecular formula but different structures, is known as Isomerism.

 Isomers-
Isomers are molecules with the same chemical formula, but different chemical
structures.

Example-
For instance, each of the 5 alkanes below has the chemical formula C 6H 14 (Hexane):

In the above set of molecules, only the first one is a "straight chain" of carbon atoms.
The remaining four have "branches" from the main chain.

The International Union of Pure and Applied Chemistry (IUPAC) has established
rules to systematize the naming of branched hydrocarbon molecules.
 A brief summary of those rules is presented here.

1. Locate the longest Carbon chain and name it. (It’s the parent hydrocarbon).
2. The branches (substituents) are located in the parent hydrocarbon chain and
named.
3. Branch names are derived from their base hydrocarbon molecule(Alkyl group):

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