How many structural isomers can you draw for pentane?

Explanation

Pentane `(C_(5)H_(12))` has a skeleton of five carbon atoms.it can exist as a straight chain as well as two branched chains. There are three structural isomers for the hydrocarbon which is an alkane.
`underset("Pentane")(H_(3)overset(1)(C)-overset(2)(C)H_(2)-overset(3)(C)H_(2)-overset(4)(C)H_(2)-overset(5)(C)H_(3))" "underset("2-Methylbutane")(H_(3)overset(1)(C)-underset(CH_(3))underset(|)overset(2)(C)H-overset(3)(C)H_(2)-overset(4)(C)H_(3))" "underset("2,2-Dimethylpropane")(H_(3)overset(1)(C)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(.^(2)C)-overset(3)(C)H_(3))`