Com OH 1. Eisomer D' -CO2H 2. Zisomer Me CI. 3. cis isomer (H;C)2HC - OH 4. trans isomer CIH,CH,C OMe

To name an alkene by the (E)-(Z) system, assign the priority order of the substituents on both the carbon atoms according to the Cahn–Ingold–Prelog rules. If two first priority groups are bonded to the same side of the carbons of the double bond, the alkene is the (Z) isomer and if two first priority groups are bonded to the opposite side of the carbons of the double bond, the alkene is the (E) isomer.

To name an alkene by the cis-trans system, at least one common group (may be hydrogen) is required. If two same group are bonded to the same side of the carbons of the double bond, the alkene is the cis-isomer and if two same group are bonded to the opposite side of the carbons of the double bond, the alkene is the trans isomer.