Descriptive lnorganic Chemistry at the Second Year Level Michael J. Webb' and Geoffrey W. Rayner Canham Memorial University of Newfoundland, Sir Wilfred Grenfell College, Corner Brook. Newfoundland, Canada A2H 6P9

The oast several vears have seen considerable debate con- cernini he amouncof descriptive chemistry which should be included in high school and undergraduate courses. Confer- ences such as those held at McMaster i'niversity in 1 9 Z ( 1 ) and at the University of Rritish Columbia in 1979 (2) have addressed this quest&. A recent issue of THIS JOURNAL (3) also contained a number of opinions.

The view is growing that such programs as Chem Study have overemphasized theoretical concepts a t the expense of descriptive chemistry and that the balance must be restored. There appears to be little agreement, however, on the question of exactly what descriptive material should be included in high school or undergraduate courses. This stands in stark contrast to the aonarent uniformitv of introductorv eeneral chemistrv coursesL&th respect to such physical chemistry topics as stoichiometrv. the eas laws. acid-base calculations. etcetera. The fact thaiieachirs know what to cover when dealing with introductorv nhvsical chemistrv. and have no such certaintv

- A . with introductory descriptive chemistry, is perhaps one of thk reasons why the quantity of descriptive chemistry being in- cluded is only slowly increasing. I t is our opinion, therefore, that curriculum development is now of great importance.

We here present our experience with the descriptive inor- aanic chemistry component of a second year course in inter- mediate chimistry taught a t Sir Wilfred Grenfell College. This bas involved the selection of topics to be covered and <he locating of good resource materials. The latter has posed some problems, particularly in terms of obtaining a suitable text. I t is hoped that our findings will assist other instructors faced with a similar task.

Course Content Our second vear course in intermediate eeneral chemistrv

treats, at a higLer level, many of the topics yntroduced in fir; year. The general subject areas are as follows:

Thermodynamics and Thermochemistry Acid-Base Chemistry Solubility and Complex Ion Equilibria Reaction Rates and Mechanisms Electrochemistrv Bonding, including Molecular Orbital Theory The Solid State, including Radius Ratio Rules and Crystal Pack-

ing Descriptive Inorganic Chemistry

Within this two-semester course the descriptive inorganic chemistry section occupies approximately five weeks of lec- tures.

The Descriptive Inorganic Chemistry Component At the first year level in this institution students meet some

descriptive inorganic chemistry. The emphasis is on period- icity, notably the similarities in behavior of elements in a given group of the periodic table and the comparison with elements in other groups. The two laboratory sessions in qualitative analysis which are included require a discussion of such in-

Presented, in part, by M. J. W. at the ninth College Chemistry Camda Conference, Corner Brook, Newfoundland, June 1981, under the title "Descriptive lnorganic Chemistry: Some Teaching Aids." ' Author to whom correspondence should be addressed.

formation as the reactions of acids with sulfides, carbonates, etcetera, and the solubilities of common salts.

I t was decided that students might benefit from a different approach to descriptive chemistry at the second year level. The fairly general view of periodicity is reviewed only briefly. Approximately three lectures are devoted to scanning the trends in physkal and chemical propeniesof theelementnand their simple compounds across the third period and in Group IVA. The latter is oarticularlv valunhle in temuerina the na- tion, often developed by beginning students, th i t all ilements in the same erouo behave essentiallv identicallv. The dis- ~ ~~ ~ ~~ ~

cussion of ~ G u p ~ V A clearly illustrates the treni from non- metallic to metallic behavior uoon descendine the eroun.

Following the review of p&odicity, we &ke a l inked number of elements and studv their chemistrv in =eater depth. We believe that this comb~ements rather than &tracts from the earlier ~eriodic view. Fur each of the chosen elements the following pdints are discussed:

(1) Physical and chemical properties of the element, (2) Occurrence of the element in nature, its extraction and uses, (3) Important compounds, including their industrial preparation

and uses, and (4) Other points of interest, such as the biological role of the ele-

ment and its compounds.

The lecture material is supported by five weeks of quali- tative analysis in the laboratory, plus experiments invdving the synthesis and properties of sodium thiosulface and cop- ner(1) oxide. Other exoeriments. such as the svnthesis a i d Hna~ysis of an oxa~a to ioba~ta te ( i~~) complex aLd an exami- nation of the oxidation states of vanadium. while nrimarilv quantitative and analytical in nature, in part $ewe tdreinforck concepts introduced in lectures.

Industrial chemistry is underemphasized in today's cur- riculum and therefore has been stressed in our lecture mate- rial. By careful selection of thr elements tu be included, many important industri~l ~rocessrs can be described.'l'he ten el- ekents discussed dur.ing the past academic year were

Sodium Carbon Nitrogen Sulfur Iron Aluminum Lead Oxygen Chlorine Copper

The decision to include as much industrial chemistry as possible poses considerable problems in our location. The West Coast of Newfoundland is not a heavily industrialized region and is far removed from industrial centers. Most stu- dents we encounter have no conceot of the substantial dif- ferences between laboratory methods and their industrial countemarts. Therefore. it is essential that students be able to see for themselves the wbrkings of industry in order to arasp the scale of industrial processes and hence their - - commercial importance. Fortunately, there are many audio- visual aids which can help to overcome this difficulty.

Audiovisual Alds We have frequently heard it said that there exists a paucity

of materials for use in teaching descriptive chemistry. An examination of the audiovisual aids on the market leads to the opposite conclusion; the number available is so vast that a comprehensive evaluation is difficult, if not impossible. As can be seen, many of the aids which we have chosen to use relate

1012 Journal of Chemical Education

directly to industrial chemistry. Those which we have found particularly helpful are listed below:

(a) Movies: "Chemical Familiesn-Chem Study, University of California "The Marvelous Mineral"--Canadian Salt Company, Halifax,

Nova Seotia "Manmade Diamonds"-General Electric Educational Films,

Scotia, NY "Nitric Acid"-Chem Study, University of California "Sulfur: Its Physical State and Properties2'-Encyclopaedia

Britannica Films, Wilmette, IL "Chlorinen-Canadian Industries Ltd., Dorval, Quebec The Coppermetalsn-ArrowHead Metals Ltd., Toronto, On-

tario

(b) Film Loops: "Eleetrolvsis of Salt Water9'-Hubbard Scientific Co., North-

hrook,i~ "Electrolysis of Molten Saltn-Huhhard Scientific Co., North-

brook, IL "Paramagnetism of Liquid OxygenM-Ealing Film Loops,

Cambridge, MA "ronp IB Elements: CopperXKalmia Co., Concord, MA "Catalvsis in IndustrvM-Shell International Petroleum Co.,

on don, England

( c) Filmstrips: "The Transition Elements'-Pooular Science Publishing Co., - - ~ ~ - - ~ ~ ~ ~ ~ ~

New York, NY "Lead: Its Extraction and Used-Royal Institute of Chemistry,

London, England

(d) Slide Sets: (all from Nicholas Hunter Filmstrips, Oxford, England)

"Chemicals from Salt: Electrolvtie Processes" ~~ ~

"Alurnlnum: Raw Materials and Purification" "Sulfurl< Arid: The Conrarr Pn,rers" "Iron ond Steel: Extraction of Iron"

Textbooks Our greatest difficulty has involved the choice of a course

text. We have been seeking a general text appropriate for a second year rather than a text for a first year course which also contains sufficient descri~tive inorganic material.

While the treatment oidesrript& inorgnnic chemistry is acce~table in many general texts. of which we provide some examples (4-8), nine of these books present theoretical con- cepts a t the level required by our second year program. Indeed, we have only encountered two general texts which contain an appropriate treatment of the relevant physical chemistry topics, namely those of Mahan (9) and King (10). In fact, we have adopted Mahan's text, and faculty teaching the same course on the St. John's campus of Memorial University has adopted King's hook. However, these two books provide in- appropriate or inadequate coverage of the descriptive inor- ganic chemistry topics described earlier. I t should perhaps be noted here that physical chemistry texts, such as those of Alberty and Daniels ( I I ) , Barrow (12), and Atkins (13), are too advanced for our second year students.

We have examined various inorganic chemistry texts to assess their suitability. Many of them, such as those by Hu- heey (14), Purcell and Kotz (15), and Mackay and Mackay (16) emphasize structural and mechanistic aspects of the subject and clearly do not suit our needs. However, there are a number of books of a more descriptive nature on the market, most of them published in the United Kingdom (17-21). Wilson's book, which is quite condensed and has an industrial emnhasis. was eventuallv adooted for student use as a SUP-

plement to Mahan's text. In addition to texts examined for possible adoption, many

works have been found useful as refeience sources for various

aspects of descriptive inorganic chemistry. The most fre- quently consulted, recently published examples are indicated (22-26). Many older hooks are also gold mines of useful in- formation, including industrial chemistry (see, for example, 27-29). While it took a great deal of time to locate some of it, we believe that appropriate textual and reference material does exist to support a descriptive inorganic chemistry course.

Concluding Remarks While the ahove discussion has concerned the second year

general chemistry course mentioned a t the outset, our com- ments on the descriptive inorganic chemistry component of the course have potentially a much wider application. The inclusion of industriallv-based material is a resDonse to the fact that this interesting and important aspect of chemistry is usually omitted from high school and freshman proarams. p ow eve;, much of the material could be covered a t those levels. The audiovisual aids and books which we have cited will, we hope, he of use toany high sehuol or fres..man chem- istry teacher who wishes to discuss the chemistry of the ele- me& we have indicated.

Acknowledgment We are grateful to our colleagues on the St. John's campus

of this Universitv who have commented on our inoreanic course outline, and in particular to Dr. Howard Clase for his heloful surrrstions. Wr also thank Dr. Robert Perkinsof this coilege f&-his assistance in locating several of the movies referred to ahove.

Llterature Cited (1) "New Directions in the Chemistry Cuniculum," Pmeedings 0' an International

Conference on Introductory Chemistry, MeMaster University. Hamilton. Ontario, June 1978.

(2) Whifla. A,, and Thompson, R. C.. "The Teaching oflnorganie Chemistry," Reporta on a Sym~mium held s t the University of Britiah Columbia, Vanmuver, British . . . . . .. . .

(3) J. CHEM EDUC.,! (4) Whitten. K. W., s

Ssunders.Phila 151 Keenan.C. W.. KI

rn~llmhia . T ~ ~ ~ ~ 1979. 57,761-777 (1980). nd Gailev. K. D.. "General Chemistrv with Qualitative Analvsis." delphis, i k . einfelter. D. C.,and Wwd. J. H.."Genersl Coll~ge ChemisW"6th

Ed.. Harper and Row, New York. 1980. (6) Nebergall, W. H., Holizclaw, Jr., H. P., and Robinson, W. R.. "General Chemistry,"

6th Ed.. Hesth,laxington, MA, 1980. (7) Kneen, W. R., Ropers, M. J. W., and Simpson. P.."Chemimy: Fa&, Patterns, P r i n ~

(9) Mahan, B. H., "University Chemistry," 3rd Ed., Addison-Wesley, Reading, MA, 1975.

(10) King, E. L., "Chemistry," Painter Hopkins, Ssusdito, CA. 1979. (11) Alberty. R. A,. and Daniels. F.. "Physics1 Chemistry," 5th Ed.. Wiley. New York,

70s" .""". (12) Barrow. G. M., "Physical Chemistry," 4th Ed., Mffiraw-Hill, NewYork, 1979. (13) Atkinr, P. W., "Physics1 Chemistry," Freeman, San Francism. 1978. (14) Huheey. J. E., "lnoxanic Chemistry," 2nd Ed.. Harper and Row, New York. 1978. (15) Purcell. K. F.. and Kotz, J. C., "An lntrodvction to Inorganic Chemistry," Saunders.

O h .ao* ' ,., .=-". (16) Mackay, K. M., and Maekw, R. A., "Introduction to Modern Inorganic Chemistry,"

2nd Ed., Infertext. London, 1973. (17) Liptrot. G. F.."Modern lnargmie Chemistry," Milk and Bwn, London. 1971. (18) Holdernes, A., "Advanced Level Inorganic Chemistry," Heinemsnn, Lundon. 1979. 119) Wilson. D. E.. "Essential Ideas in lnoqanie Chemistry," Hodder and Stoughton,

London. 1978. Blown, G. 1,"lntroduetion to Inorganic Chemistry,"Longmsn, London, 1974. Rochow, E. G., "Modern Descriptive Chemistry: Ssundera, Philadelphis. 1977. Thompmn.R. iPAitor),"TheModern InorgsnicChemicsl~Industry."TheChemicsl

Society. London, 1977. Selinger, B., "Chemistry in the Marketpha"2nd Ed..Austrdian NationalUnivemity

Press, Canberra, 1978. Moore, J. W.. and Moore, E, A,, "Environmental Chemistry," Aesdemie Press, New

"-.a, ,am .".", .".". Fiabane,A. M.,and Williams.D. R.,"TheP<nciplesof Bio-InovanicChemistry?The

Chemical Society. London. 1971. Hill. G. C.. and Holman. J. S.. "Chemistrv in Context," Nelmn, Sunbury on Thsmes,

~ idd lesex , 1978. Goddard, F. W., and Hutton, K., "A Schml Chemistry for Today," Longmans. Green

and Co.. London, 1950. Watt, G. W.. Hatch. L. F., and Lagowski, J. J.. "Chemistry." Norton, New York,

1964. Partingtan, J. R, "General and InorganicChemistry," 3rd Ed., MacMillan. New York,

1958.

Volume 59 Number 12 December 1982 1013