what are the formulas of the geometric isomers 1,3-dimenthylcyclopentane?

Question

this is alkanes experiment

Answer 1

from: http://www.chemguide.co.uk/basicorg/isomerism/geometric.html


Isomers are molecules that have the same molecular formula, but have a different arrangement of the atoms in space. That excludes any different arrangements which are simply due to the molecule rotating as a whole, or rotating about particular bonds.

Geometric isomers are the cis/trans isomers. In your molecule it is the methyl groups that will be cis (same side) or trans (opposite sides) to each other on the pentane ring.

Therefore the geometric isomers are
cis-1,3-dimethylcyclopentane and trans-1,3-dimethylcyclopentane.

(You have to draw the structural formula with the bonds indicating that the methyl groups are on the correct side/face of the cyclopentane.