[coolguy99]

Hey, just a quick question that I'm confusing myself over.




I originally wrote down cis/trans isomers, only to find that they're identical. Are they identical because you can name them the same? I don't really see it.

[renge ishyo]

The carbon in question is only chiral if it has 4 nonidentical groups surrounding it. Directly attached to the carbon of interest in the this problem is a hydrogen, a methyl group, and two methylene groups. Since the methylene groups are the same you have to keep looking further and further out from the methylene groups on each side to find a mismatch at which point you can conclude that the carbon of interest is chiral. In this case, you never find a mismatch...so the carbon in question is not chiral. Since its not a chiral carbon even if you switch the 3D in the picture it doesn't matter, you are looking at the same molecule.

[UnintentionalChaos]

A quick visual way to confirm that this molecule is not chiral is to imagine a rotation axis through the "center" of interest and the opposite carbon on the ring. Now, rotate it 180 degrees. The ring remains unchanged, the carbon that was pointing out at you rotates back into the page, and the hydrogen that was pointing back into the page is rotated up and out of the page. This is identical to the second drawing you have, so the molecule is not chiral.