Testing Your Organic Chemistry Knowledge to Reinforce ...

Testing Your Organic Chemistry Knowledge to Reinforce Comprehension and
Understanding using Web-based Multiple Choice Questions
Andrew Boa and Jason Eames*
Department of Chemistry, University of Hull
a.n.boa@hull.ac.uk; j.eames@hull.ac.uk
88. Shape 2
Which of the following structures is trigonal planar?
*a. A
b. B
c. C
d. D
e. E
Correct Answer Reply:
A trigonal planar arrangement can be found in two types of molecules where:
(i) no multiple bonds are involved, the central atom has a maximum of three lone or
bonding pairs of electrons.
(ii) three sigma bonding pairs of electrons are used on the central atom, but a fourth
bonding pair of electrons is involved in a pi-bond - for example, in alkenes.
In these examples, C contains a lone pair of electrons so is pyramidal not trigonal planar.