Lecture #8, Friday, October 8th

Transition metal complexes fascinated chemists back to the early ages due to their color. In the transition metal unit we will talk about the bonding theories chemists use to explain the differences in color for the observed transition metal complexes.

Remember that for our eyes to observe color, an electronic transition must be in the visible region of the electromagnetic spectrum. A transition occurs when an electron is excited from the ground state (an orbital of lowest energy containing an electron) to an excited state (an orbital of higher energy that is empty). In order to understand the reason behind the color in these complexes always keep two things in the back of your mind: #1 How many d electrons does a transition metal ion possess, and #2 What is the energy of the orbitals containing the electrons (or more importantly, what is the energy difference between the empty orbitals).

Before we get into the meat and potatoes of transition metal chemistry, and more exciting bonding theories (humor me, I'm a big dork and this stuff is pretty neat to me), we need to discuss some background information on transition metal complexes.

I went over how to properly determine the electron configuration of a transition metal cation. Be sure you are able to do this. We then reviewed the electromagnetic spectrum and I mentioned how unique it is to observe excitations in the visible spectrum since the energy of the visible spectrum takes up such a tiny portion of the visible spectrum.

We then discussed coordination compounds and the early work of Alfred Werner. This led to our modern day notation of transition metal complexes and the term isomer.

Inspiration Quote:
"If you don't have time to do it right, when will you have time to do it over?"
-John Wooden

Songs Played Before Class:
Sum 41 - In Too Deep
Brad Paisley - Water