In his third post, Retread looks at some of the physics and math needed and used by chemists.
Now that the answer book to Jones has arrived (23 May) I’m going to start over from the beginning, this time doing all the problems. Mathematicians are fond of saying that it isn’t a spectator sport, and that problems must be done to really grasp the material. I’m not so sure that is true for chemistry, but I’ll take excimer’s advice.
I’d gone through the first 300 or so pages of Jones and it’s apparent the two textbooks are wildly different in the way they approach the beginner.
English & Cassidy start out with hydrocarbon structures. Molecular orbitals make their appearance on p. 63 (remember the book only has 442 pages of text). They are introduced as follows: “A somewhat more easily visualized physical picture of a double bond is given by a relatively recent theoretical development known as the molecular orbital theory.” Recall that there are only six three dimensional drawings in the first 100 pages of E&C. Four of them involve orbitals.
Jones drenches the reader in atomic and molecular orbitals using all the graphics at his disposal. One needs to step back in time to realize the mathematical armor the high school graduate possessed in ‘56 entering college. Outside a few of the great academic high schools in the USA (Central High in Philly, Bronx High School of Science) calculus was simply not taught in US public high schools. The thinking was that is was so hard that it would destroy the brain of anyone under 18. There was a giant dose of anxiety on taking it for the first time. Just about all the undergraduates in the math courses I audited had a year or two of calculus in high school and some were exposed to it in the 8th grade.
So junior chem majors back then didn’t have the apparatus to tackle the Schrodinger equation etc. Formal quantum mechanics wasn’t taught to us back then. Even though the department had Walter Kauzmann, who wrote the influential “Quantum Chemistry” in ‘57, and who taught physical chemistry (which we all took), quantum mechanics wasn’t really discussed in the course.
The department did introduce us to quantum mechanical thought. As juniors we were required to read a book “The Logic of Modern Physics” by P. W. Bridgman, written in 1927 in the early heyday of quantum mechanics. I found it extremely irritating. It argued that all we could know was numbers on a dial reporting the results of a measurement. The notion of particle trajectory was to be abandoned, etc. etc. Jones skirts the issue on p. 10 where he talks about the node in the 2S orbital, a place where an electron is NEVER found. An electron following a trajectory as we know it macroscopically could never pass through the node. If you like thinking about such things, I recommend just about anything a physicist named Mark P. Silverman writes. In particular, Ch. 5 “And Yet It Moves: Exotic Atoms and the Invariance of Charge” in his book “A Universe of Atoms, An Atom in the Universe” deals with the issue of the ‘motion’ of an electron in an atom.
I have a friend, a retired philosophy prof from Columbia, who dismisses all biology and chemistry as ‘anecdotal’. The only thing he regards as solid is Godel’s proof. I told him he better hope he’s wrong if he ever gets sick. In a similar vein, Bridgman is as wrong as he can be when it comes to chemistry. Why? Because the theory behind chemistry may have its origin in numbers on a dial, but it gives rise to gazillions of successful predictions about reactions, structure and spectra. Theory is immaterial, but it guides chemists (it’s the old Cartesian dichotomy between flesh and spirit). Following chemistry in a peripheral fashion during my years in medicine by reading what appeared in Nature and Science (on a superficial level), it seemed that the work in gas phase kinetics was just confirming (always good) what we ‘knew’ back from ‘58 – ‘62. The one surprise was the reversal (p. 245) of the acidity of primary, secondary and tertiary alcohols in the gas phase.