Question

What are isomers?explain this.

Answer 1

isomersare nothing but  the different types of structure.if one or more number of structures are present for a single compound,they are called isomers.
for example lets take a common compound butane. 
if we write the structure for it,we can get it in many other forms too. 

isomers of butane are,
n butane
iso butane

each of them has a unique structure.
n butane is a straight chain. 
iso butane is branched.

if you see in pentane,we have 3 structural isomers.
n pentane 
neo pentane
iso pentane
neo pentane is double branched.this is not in butane .

at last,all the compound and the molecular formula are same but the structures differ.these are isomers.

same compound having different structures is called isomers.look at the attachment for structures of both compound.

hope it helps!!!

Answer 2

isomers are those compound having same molecular formula but different structural formula.

hope it help u