A PERIODIC SYSTEM of the ELEMENTS E. C . PAYNE* Vila Park, Illinois
A somewhat original Periodic System i s presented, consisting of a n octagonal cardboard prism, its faces divided into rhombs by a descending helical band. Each rhomb is assigned to a n element. The distinction behuea the two families of a h column of the Mendeldej chart (e. g., Li and Cu families) i s clarified by elevating one of them (Cu family) above the surface of the prism, and connecting these raised s@cs to form a continuous series (e. g., Sc through Z n series). The metallic triads of 'column 8 occufiy the faces of parallelepiMs, set upon rhombs in column 8. The rare earths appear on the inside sutjace, through a w i n d m cut where space 57 would be. After speculation upon the nature of the last, unfinished period, there is listed, a n o p i n i a of the &nci@l dificullies and pitfalls acountned in the cunstruction of a n original system.
T
rangement of his own. In laboring over this fascinating and intricate puzzle, he cannot fail to learn a great deal of chemistry, in addition to fixing the sys-
HE number of articles on the periodic system which have appeared in THISJOURNAL in recent years, and especially that series by Qnam and Quam,l during 1934, have stimulated the author to a fresh study of that classification. m i l e no system which has been devised is perfect, some of them do express the relations of the elements in such clear and usable form that any further arrangements might seem like new proofs of the Pythagorean proposition of geometry, demonstrating the ingenuity of the inventor, rather than adding to useful scientific knowledge. There is, however, a justification for such a work. That is the stimulation of student interest in this key to inorganic chemistry. That it should occupy a prominent place in the course in general chemistry is universally admitted. Nevertheless, its potentiality as a guide to the chemistry of the elements often is not effectively utilized in pedagogical practice. I t should be introduced early in the course, as soon as the elements are taken up by families, and their relations discussed. Later, when the student has learned a little of atomic structure, his introduction to a number of periodic systems serves to stimulate his in his memory, even though failing to prointerest in the relations of the elements, and the re- tern sultant study will lead toward the integration of the duce a creditable original scheme. Probably no system yet published approaches in chemistry which he has learned, or may learn. He may even be sufficientlv interested to attemot an ar- usefulness the modified Mendeleeff chart. In spite of some theoretical objections, it remains the cle&est * Former address Butler University. Indianapolis, Indiana. 288 and most convenient for general classroom use. Some 1 a"ax,G,N, AND M, B,, IklSJOURNAL, 27, (1934). of the systems which seem better from the theoretical
point of view, such as the helixes of Harkins-Hall9 and of Schaltenbrand,Z lack clarity and ease of comprehension. The author ventures to present a system incorporating something of the graphic clarity of the simple Mendel& chart, with the theoretically nicer arrangement of the three-dimensional models. It incorporates the basic principles of the Harkins-Hall
helix and of the "castle" of C o ~ r t i n e s . ~It is constructed of cardboard in the form of an octagonal prism. A ribbon is wound spirally about this figure, barber-pole fashion, dividing its faces into rhombs. The "pitch" of the spiral is such that, upon completion of the circuit, the ninth rhomb falls just below the b t . The topmost space, thus set off, is occu~iedbv helium;
