Ch7 Lec 1

(4/19/20, bes)

Greetings...and welcome to Chapter 7!

Do you recall that last chapter titled "Thermochemistry" was an introduction to the larger field called Thermodynamics...and that Chem-312 is a semester long course on "thermo" that all chem/biochem students will take with me (bes). Well, chapter 7 is similar. The "electronic structure of the atom" is described by "quantum theory"...and Chem-322 is a semester long course titled Quantum Mechanics, also taught be me. So these two chapter are near and dear to my heart, but we only skim the surface of these topics in gen chem.

There is a lot of information in this chapter, so again stick with me and focus on these lecture notes. I do want you to skim the section, but as it is most important for you to understand the topics that i highlight in these notes.

ps. reminder there is a WA from Ch6 due on Tues at 5 pm.

Sec 7.1: From Classical Physics to Quantum Theory

Whether you took physics in high school or not, you are aware of concepts such as speed (miles/hour), acceleration, gravity...and maybe a little related math. These introductory physics topics are often highlighted with examples of falling apples (Newton), throwing baseballs, hitting billiard balls ("pool"), or launching rockets. A common theme of all these topics is that there is a "mass" and if you put energy into it, then it moves; sometimes it transfer it energy to another similar object (like in billiards) and sometimes you just want to know where the ball or rocket will end up if you throw/launch it at a certain angle to the ground. All of these introductory physics topics do an awesome job at explaining the things around us and even does a great job with the motion of planets and our entire solar system (Astronomy <-- a subfield of physics). All of these concepts fall under the heading of "classical mechanics"...with the term mechanics meaning how things move.

As humans became aware of atomic/molecular structures (1800s) we needed a way to describe their behavior very much like Newton described the behavior of an apple falling from the tree. When early day scientists/physicist used "classical mechanics" to describe the behavior of atoms and molecules, these theories often did not describe their behavior well. It is sometime said that classical mechanics "failed" to describe atomic systems, but this is way too harsh...side note: i hope that all of you know that there are 2 main types of "heads" on a screw...flat and cross (aka Phillips head). If you need to remove a Phillips head screw and you use a flat-head screwdriver, is it fair to say that the flat-head screw driver "failed" at removing the screw or is it better to place blame/error on the user...ie don't use a flat-head screw driver to

Sec 7.9: The Building-Up Principle