Fred Basolo Northwestern Univers~ty Evanslon. lL 60201
Can Descriptive Inorganic Chemistry be Taught in General Chemistry Courses?
I have always maintained that it is possible to do an excellent job with a beginning chemistry course which contains an appreciable amount of descriptive inorganic chemistrychemical reactions, industrial processes, and syntheses. This is the chemistry which students are most likely to remember for a lifetime, and that it is important. However, developments in chemical education during the last two decades have finally convinced me that the oresent answer to the auestion-"Can descriptive inorganic chemistry be taught in general chemistry courses?"-is definitely no. In my opinion, the primary reason for this is that we now have ageneration of chemistry faculty and textbook authors who as students themselves had an absolute minimum exposure ta chemical reactions, syntheses, and industrial processes. It is understandable that these faculty will continue to teach the topics in chemistry which were taught to them and with which they are most familiar. In conversation with such facultv I often hear them aive lio service to the need for more "real" chemistry in our beginning courses. When asked why they do not attempt to teach more descriptive chemistry if they think it is important, I am given various reasons. The three followine reasons are most often mentioned: ~
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(1) It is not possible to teach descriptive chemistry without boring the students. (2) There is no time far descriptive chemistry hecause of having to teach all of the other important topics which must be covered. (3) . . There is no modern general ehemistrv textbook which adequately treats descriptive chemistry,
These are three valid reasons for not teachine more de, this scriptive chemistry in beginning courses. ~ o w e c e rin short article I wish toresoond to each of these reasons, and I hope that I can convince so~nt:readt:r.i that it should he p ~ sihle to wercmne rhwe diff~culric~. Hrfore addressing the three reasons, I will justify the need for teaching more descriptive chemistry to beginning students. Less than five percent of the students who take first year chemistry become professional chemists. The other ninetyfive percent eventually are the doctors, dentists, engineers, lawyers, politicians, social workers, etc. which make up our societv. Manv of these students take onlv one vear of chemistry. w h a t do these people remember about their chemistry course 20 or 30 years later? If they were among the fortunate generation of students that had some descriptive chemistry with lecture demonstrations and some wet qualitative analysis in the lahoratory, they can recall the spectacular thermite reaction which was hot enough to melt an iron disk, the explosion of a mixture of hydrogen and oxygen, and the rotten-egg smell of H B in their aual lab. If thev were among the unfo&nate generation of s&dents that learned nume&s orincioles, a lot of bondins, worked many orohlems, hut had few lecture demonstrations and a minimJm of chemical reaction type experiments in the laboratory, they often remember almost nothing of their one year of chemistry. They have no appreciation of why high sulfur coal is a problem, because they have never smelled sulfur dioxide. Some chemistry faculty agree that more descriptive chemistry would he good for nonchemists, hut they think that there are more important topics which must he taught to students who are to become professional chemists. I a m absolutely certain that this is not correct. It would he correct if chemistry majors were taught descriptive inorganic chemistry in more advanced courses. Unfortunately, this is not
being done in advanced level inorganic courses, which frequently are devoted to baby physical chemistry. Many of us have been aware of this for years, as a result of grading orientation examinations " eiven to enterine graduate students with outstanding credentials from good chemistry departments across the country. We also know this from working with graduate teaching assistants who do an excellent job; except for the one or two weeks when some of us insist on teaching descriptive chemistry. When Davenport dramatized this problem with his reference to the graduate student's answerthat "AgCI is a pale-green gas,"~many of us had been aware for years of such answers by beginning graduate students. What is more disturbing, however, is that even during their oral defenses of thesis examinations some students exhibit complete understanding of the very sophisticated systems which they studied hut fail miserably on questions of descriptive chemistry. I have experienced several examples of this on thesis committees, hut, 1 will relate only the most recent one. This student had done a fine ioh of orenarine several rather unique copper complexes in thk hope that some of these would function as synthetic oxyeen carriers. Most of the compounds were new and elemenial analyses were reported, but in no case was the percentage of copper given. When asked ahout this we were told that our analyst only does C, H, and N analyses. We pursued this further asking why the candidate could not have determined copper, only to learn that the candidate knew almost nothing about the general chemistry of copper. The kinds of questions asked were such that any PhD chemist should have known the answers, and what was even more incredible is that this oerson was about to become a PhD inorganic chemist. I repeat that we do not do chemistry majors a favor by not teaching more descriptive inorganic chemistry in general chemistry courses. Now for some brief comments on each of the three reasons given for not teaching more descriptive chemistry. The one that students get bored can often he disposed of by making the point that this may result from the instructor not being very excited and enthusiastic about the subject. Students are smarter than we give them credit for, and they are quick to detect which topics the teacher finds important. I t is also claimed that students refuse to memorize reactions (yet they do not object to memorizing and using repeatedly and mechanically in solvingproblems, equations such as P V = nRT and AG = AH - TAS). I agree that students should not memorize specific reactions. They should learn how to use the periodic table, and they should be told about various types of reactions such as combination, decomposition, replacement, metathesis, and acid-base. They should have a qualitative appreciation as to why elements and compounds undergo these types of reactions, and with the aid of the periodic table to make educated guesses as to the tvoes of reactions that certain elements and compunds a r e likely to undergo. Memorization is taboo, hut students can get excited about chemical reactions providing their teachers ;hare this interest with them. If we add more descriptive chemistry, then what goes from our presently crowded general chemistry courses? This is something- that no two of us will ap-ree uoon comoletelv. I can " only express my personal opinion that gas laws, bonding (hevond the Lewis dot diaerams). kinetics. and thermodvnamics can he sacrificed. students who take more chemistiy will examine these topics in a more appropriate manner, whereas the other students will have no need for any of this
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Volume 57, Number 1. January 1980 / 45
material or would not recall a sufficient amount to make use of it were it needed. Finally the textbooks in general chemistry need authors who want to teach students descriptive chemistry more than they want to sell textbooks by going along with what seems to he fashionable at the moment. The tahles of contents of present textbooks clearly reveal that the emphasis is placed on the principles of chemistry using the "standard" few chemical reartions tu illustrate these principles lur as I have had students tell me that chemistry is not real reactims, hut
46 1 Journal of Chemical Education
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merely A B C D).The emphasis is wrong for a heginning course, where chemical reactions should predominate with the use of generalizations as to why and how such reaction types take place. This definitely does not mean that descriptive chemistry should he treated as it was years ago when each chapter was devoted to a family of elements from the Periodic Table and the chapter consisted of giving the discovery of the elements, their preparation. and reactions. If au. . ..properties. . thors are no more imaginatiw than that, we can rest assured that descriptive chemistry is doomed to failure.
