Chemical Education Today
Especially for High School Teachers The Heaviest Elements
by J. Emory Howell
Secondary School Feature Articles
Hanging on a wall in most chemistry classrooms is a periodic table that contains a smaller number of entries than the 112 known elements. Several of the heaviest elements are likely to be indicated with designations that appear particularly strange to students, such as Unh for element number 106. The periodic tables printed in textbooks often contain these designations as well. Changes are expensive for publishers of wall charts and textbooks, so the lag between discovery or formal naming is in part a matter of economics. And even when new element symbols are added, most school instructional budgets do not permit frequent replacement of expensive wall charts. The periodic table appearing in this month’s “Viewpoints: Chemists on Chemistry” article by Hoffman and Lee (p 331) contains entries for 112 elements, although no symbols are given for elements 110–112. The temporary symbols and names for elements were established by the International Union of Pure and Applied Chemistry (IUPAC) in 1979 (1, 2) but they never were popular with workers in the field. Because the system of temporary naming does not commonly appear in textbooks, the four rules for determining the IUPAC-approved temporary name are repeated below as a convenient resource: 1. The name is derived directly from the atomic number of the 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 digits that make the atomic number and are terminated by ium to spell out the name. The final n of enn is elided when it occurs before nil, and the final i of bi and of tri when it occurs before ium. 3. The symbol of the element is composed of the initial letters of the numerical roots that make up the name. 4. The root un is pronounced with a long u, to rhyme with moon. In the element names each root is to be pronounced separately.
These rules can be applied to understand the temporary symbols that still appear on many periodic tables, as indicated in the table below. There was a long-running controversy over naming the elements in the table, but permanent names and symbols were approved in August 1997 and eventually new textbook edi-
t Before There Was Chemistry: The Origin of the Elements as an Introduction to Chemistry, by Neil Glickstein, p 353.
tions and periodic tables will reflect the IUPAC decision. It is likely that elements 110–112 will receive official names much more quickly than did elements 104–109. Because experts in the field find it simpler to say “element 110” than “ununnilium”, it is possible that temporary names will find little use in the future. Nevertheless, it is easy to follow 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 the chemistry of the heaviest elements, this issue contains four articles related to the discovery of the elements and nuclear reactions. A Secondary School Chemistry feature article, authored by a high school teacher (see box), explains how a study of the origin of the elements can be used as a theme for introducing chemical and physical concepts to students. Authors Olbris and Herzeld describe a new game for learning about nuclear reactions (p 349). The game board can be downloaded, free of charge, from a Web site. Previous issues of JCE have carried articles that trace the progress of discovery of the heaviest elements. Nobel laureate Glenn T. Seaborg has authored several articles that have been published in JCE. Three of my favorites are ones in which he provides historical context and insights into the development of understanding that made new discoveries possible (3). The personal recollections of the author make the historical aspects much more real and interesting than textbook accounts and provide a lively connection between chemistry and history. High School Program at the Anaheim ACS Meeting See page 304 for information about the outstanding program that will take place March 22 as part of the Division of Chemical Education Program. This event has been planned especially 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 Temporary and Permanent Symbols Appearing on Some Periodic Tables Atomic No.
Temporary Name
Permanent
Symbol
Name
Symbol
104
Unnilquadium
Unq
Rutherfordium
Rf
105
Unnilpentium
Unp
Dubnium
Db
106
Unnilhexium
Unh
Seborgium
Sg
107
Unnnilseptium
Uns
Bohrium
Bh
108
Unniloctium
Uno
Hassium
Hs
109
Unnilennium
Une
Meitnerium
Mt
Later in the same week as the ACS meeting, the NSTA Convention in Boston offers many interesting sessions and events. Be sure to visit the JCE booth, #2037, to examine print and electronic media resources you can use in your classroom. We look forward to meeting and talking with you. Literature Cited 1. Pure Appl. Chem. 1979, 51, 38–44. 2. Orna, M. V. J. Chem. Educ. 1982, 59, 123. 3. Seaborg, G. T. J. Chem. Educ. 1969, 46, 626–634; 1985, 62, 463–467; 1989, 66, 379–384.
JChemEd.chem.wisc.edu • Vol. 76 No. 3 March 1999 • Journal of Chemical Education
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