One more periodic table

somewhat arbitrary eff ort to align 100 unique, individual elements in the most logical possible order for con- veniently comparing their properties. ...
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State University of Iowa, Iowa City, Iowa


simple form of the periodic table is shown in the figure. Its distinguishing feature is the method of indicating the electronic differences. The grouping of elements according t o greatest electronic similarity is immediately apparent. This table has the virtue of emphasizing the arbitrariness in assignment of elements to "major" groups. Two recent events prompt this entry into the overpopular field of periodic tables. One is a letter to the editor from S. T. Bowden of Wales,' remarking on the present state of confusion in this field and proposing tbat for teaching purposes the periodic table be standardized by an international committee. The other is the advertisement2 of a new periodic chart for classroom use, in which Sc, Y, and La are grouped with B and A1 as 111-A elements, instead of being grouped by themselves as 111-B elements as, for example, in the BOPIDEN.S. T.,J. CHEM.EDUC., 30,426 (1953). ┬ÂIbid., 30, 33(A) (Sept., 1953).



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excellent chart prepared from that of H. G. Deming and distributed widely by Merck and Co. The second event certainly illustrates Professor Bowden's point. Students may readily be bewildered by the apparently fundamental lack of agreement among various periodic tables, and some may even acquire reasonable doubt as to whether chemists actually know what they are doing. I cannot, however, share Professor Bowden's confidence, or hope, tbat universal agreement could be legislated by an international committee. Periodicity is fundamental, but any periodic table is only an artificial and necessarily somewhat arbitrary eff ort to align 100unique, individual elements in the most logical possible order for conveniently comparing their properties. The complete complexities of periodicity, in my opinion, can never be simply charted. Differences in opinion as to the best representation will therefore always exist. Actually, a proper understanding of the interrelationships of the chemical elements may be aided by an awareness of the existence of alternative periodic tables and by an understanding of their differences. For those who prefer, however, to try to minimize the possibilities of confusion, a chart like the figure, which ( a ) indicates clearly the major electronic differences among the elements, and (b) groups them solely according t o valence, has certain advantages. The grouping of elements according to greatest electronic similarity is immediately apparent. Students can see that complete justification does not exist for grouping &her Sc. Y. and La or Ga. In. and TI with B and Al. one or the other subgro& more closely resembles the first two elements of the valence group. The periodic table itself, however, is properly noncommittal. =DEMING, H. G., "Fundamental Chemistry," 2nd ed., John Wiley & Sons, Ino., New York, 1947.