2014‎ > ‎03‎ > ‎

The Trials and Tribulations of a Chemistry Teacher III

posted Oct 25, 2016, 2:14 AM by Grace Ong   [ updated Oct 25, 2016, 2:15 AM ]
The following post was first posted on Blogger on Sunday, 30 March 2014.

Sigh. Sometimes, I wonder what goes on inside a student's head during lessons... Where did all our efforts go?

common mistakes when drawing structural formulae of organic molecules

  1. This is an incorrectly drawn structure of the pentavalent transition state of an SN2 mechanism. Besides the reversal of atoms in the structural formula, this student had also forgotten to include a single negative charge for this structure.
  2. The pentavalent transition state, which has five bonds to the central carbon atom, has a trigonal bipyramidal structure. Unlike a reaction intermediate which is a well-defined species with a definite lifetime, a transition state is a theoretical structure used to define a reaction mechanism.