Question

Which best describes the structure of 2-butene

Answer 1

The 2 represents that it is a double carbon bond
it looks like..
C-C = C-C

Answer 2

The structure of 2 - butene in organic chemistry, is simply three lines connected in a zig zag based manner, where each point on the line represents a carbon atom. To make it an Alkene, here you would place another horizontal line starting from the second carbon in the molecule.