What is the difference between cis and trans 2-butene?

Cis-2-butene and trans-2-butene are isomers of the same compound, but they have different arrangements of atoms around the double bond. In cis-2-butene, the two methyl groups are on the same side of the double bond, while in trans-2-butene, they are on opposite sides. This difference in arrangement affects the physical and chemical properties of the two isomers.