What is the correct structure for trans-3,4-dichlorocyclopentene? I have to draw the structure for trans-3,4-dichlorocyclopentene.

What position should I draw the double bond at? Should I draw it as molecule 2? Because there's a trans. 

Or should I draw it as shown in molecule 1 because it didn't state? 



I feel that molecule 2 in the diagram is correct. What do you think? Where are my mistakes?
The issue here really is that the name 'trans-3,4-dichlorocyclopentene' is not really correct, as it is unspecific. It lacks stereo-descriptors, and the locant for the double bond.

Assuming that the double bond starts at the first carbon, which is usually the case if it is omitted, there are two enatiomers still possible:


(3R,4R)-3,4-Dichlorocyclopent-1-ene



See for details: National Center for Biotechnology Information. PubChem Compound Database; CID=12430197.
(3S,4S)-3,4-Dichlorocyclopent-1-ene



See for details: National Center for Biotechnology Information. PubChem Compound Database; CID=131015828.


So the structure you have drawn as 1 is (3R,4R)-3,4-dichlorocyclopent-1-ene.

The structure you have drawn as 2 doesn't really exist, as the double bond is planar, but ignoring that it would be 1,2-dichlorocyclopent-1-ene.



See for details: National Center for Biotechnology Information. PubChem Compound Database; CID=10606793.