How many structural isomers can you draw for pentane?

What are the two properties of carbon which lead to the huge number of carbon we see around us?

Draw the structures for the following.

(i) Ethanoic acid

(ii) Bromopentane*

(iii) Butanone

(iv) Hexanal

*Are structural isomers possible for Bromopentane?

What will be the formula and electron dot structure of cyclopentane?