Especially for High School Teachers

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  • Chemical Education Today

    JChemEd.chem.wisc.edu Vol. 76 No. 3 March 1999 Journal of Chemical Education 295

    The Heaviest Elements

    Hanging on a wall in most chemistry classrooms is aperiodic table that contains a smaller number of entries thanthe 112 known elements. Several of the heaviest elements arelikely to be indicated with designations that appear particularlystrange to students, such as Unh for element number 106.The periodic tables printed in textbooks often contain thesedesignations as well. Changes are expensive for publishers of wallcharts and textbooks, so the lag between discovery or formalnaming is in part a matter of economics. And even when newelement symbols are added, most school instructional budgetsdo not permit frequent replacement of expensive wall charts.The periodic table appearing in this months Viewpoints:Chemists on Chemistry article by Hoffman and Lee (p 331)contains entries for 112 elements, although no symbols aregiven for elements 110112.

    The temporary symbols and names for elements wereestablished by the International Union of Pure and AppliedChemistry (IUPAC) in 1979 (1, 2) but they never were popu-lar with workers in the field. Because the system of tempo-rary naming does not commonly appear in textbooks, the fourrules for determining the IUPAC-approved temporary name arerepeated below as a convenient resource:

    1. The name is derived directly from the atomic number ofthe element using the following numerical roots: 0 =nil; 1 = un; 2 = bi; 3 = tri; 4 = quad; 5 = pent; 6 = hex;7 = sept; 8 = oct; 9 = enn.

    2. The roots are put together in the order of the digitsthat make the atomic number and are terminated byium to spell out the name. The final n of enn is elidedwhen it occurs before nil, and the final i of bi and oftri when it occurs before ium.

    3. The symbol of the element is composed of the initialletters of the numerical roots that make up the name.

    4. The root un is pronounced with a long u, to rhymewith moon. In the element names each root is to bepronounced separately.

    These rules can be applied to understand the temporarysymbols that still appear on many periodic tables, as indicatedin the table below.

    There was a long-running controversy over naming theelements in the table, but permanent names and symbols wereapproved in August 1997 and eventually new textbook edi-

    tions and periodic tables will reflect the IUPAC decision.It is likely that elements 110112 will receive officialnames much more quickly than did elements 104109.Because experts in the field find it simpler to say element110 than ununnilium, it is possible that temporary nameswill find little use in the future. Nevertheless, it is easy tofollow the rules and arrive at these names: 110, Ununnilium(Uun); 111, Unununium (Uuu); 112, Ununbium (Uub);113, Ununtrium (Uut).

    In addition to the article by Hoffman and Lee on thechemistry of the heaviest elements, this issue contains fourarticles related to the discovery of the elements and nuclearreactions. A Secondary School Chemistry feature article,authored by a high school teacher (see box), explains how astudy of the origin of the elements can be used as a themefor introducing chemical and physical concepts to students.Authors Olbris and Herzeld describe a new game for learningabout nuclear reactions (p 349). The game board can bedownloaded, free of charge, from a Web site.

    Previous issues of JCE have carried articles that trace theprogress of discovery of the heaviest elements. Nobel laureateGlenn T. Seaborg has authored several articles that have beenpublished in JCE. Three of my favorites are ones in which heprovides historical context and insights into the developmentof understanding that made new discoveries possible (3). Thepersonal recollections of the author make the historical aspectsmuch more real and interesting than textbook accounts andprovide a lively connection between chemistry and history.

    High School Program at the Anaheim ACS Meeting

    See page 304 for information about the outstanding pro-gram that will take place March 22 as part of the Division ofChemical Education Program. This event has been plannedespecially for you and I look forward to seeing you there!While at the meeting be sure and visit the JCE booth #1051,in the exposition hall.

    JCE at the Boston NSTA Meeting

    Later in the same week as the ACS meeting, the NSTAConvention in Boston offers many interesting sessions andevents. Be sure to visit the JCE booth, #2037, to examineprint and electronic media resources you can use in your class-room. We look forward to meeting and talking with you.

    Literature Cited

    1. Pure Appl. Chem. 1979, 51, 3844.2. Orna, M. V. J. Chem. Educ. 1982, 59, 123.3. Seaborg, G. T. J. Chem. Educ. 1969, 46, 626634; 1985, 62,

    463467; 1989, 66, 379384.

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    Especially for High School Teachersby J. Emory Howell

    Secondary School Feature Articles

    t Before There Was Chemistry: The Origin of the Elements as anIntroduction to Chemistry, by Neil Glickstein, p 353.