Expert: Dr. Henry Boyter, Jr. - 12/6/2008

Question
What is the reason that Isomers differ in chemical properties yet they have the same composition? Is it possible for Isomers to have different Isotopes in their composition and this would be the reason of their differences?

Answer
You can make isomers that are different in isotopes, but that is done intentionally and is very hard.  The isotopes made of earthly sources however had the isotopes randomized during the formation of the earth, so that will not explain the differences.  These differences arise from shape differences and how the bonds are arranged.

One example I have always used is this.  Take a fifty foot pole.  It is easy to carry it throguh a door lengthwise.  Now, cut ten feet off and attch it perpendicular to the 40 foot section.  Much harder to get through the door.  Now do another ten, but on the other side of the first ten.  It will not go through the door. Put ten feet perpendicular to one of the short pieces and you have no chance.  Isotopes work the same way.