Manipulation and organic chemistry

Look at the figure above - both are pictures of bromo-chloro-flouro methane (a carbon atom connected to a hydrogen atom, a bromine atom, a chlorine atom and a flourine atom). However, these two atoms are not the same - the order in which the atoms are connected to the carbon are different. We call two molecules like this enantiomers and in order to name the molecules, we have to mentally rotate the atom such that the carbon is in the front and the hydrogen is in the back. We then rank the other three atoms in order of atomic weight and draw a circular arrow from the heaviest to the lightest. If this arrow goes clockwise, it is named (R) bromo-chloro-fluoromethane and if it goes counterclockwise, it is named (S) bromo-chloro-fluoromethane.

There is a point to this - I promise...

Last Sunday at my MCAT prep course, our instructor (an MD named Marisa) was reviewing enantiomer nomenclature with us and had this to say:

Marisa: Before taking the MCAT, you all need to make sure that you feel comfortable mentally rotating the figures in order to name the enantiomers correctly. Statistically speaking, men are better at manipulating three dimensional images in their heads.

All the men in the class smile and celebrate

Marisa: Of course, statistically speaking, women are better at manipulating men into manipulating three dimensional images in their heads.

I love my MCAT teacher :-)