zinc group and not to the alkaline earth group, these elements should be associated with Group IIB. If one retains the loops of the spiral (Figure 2) but removes the segment lines along with the symbols and atomic numbers of the elements in the area of the transition elements, a pattern is produced which makes one wonder why three of the elements difficult to place properly on a periodic table, hydrogen, beryllium, and magnesium, should occupy positions on the loops of the spiral in the same general area as the transition elements. Are these three elements in periods 1, 2, and 3 in some way analogs of the transition elements of periods 4, 5, 6, and 7? VALENCE
Oxides and Double Periodicity. The valence with respect to oxygen starts a t 1 with Group IA and increases counterclockwise to a maximum of 8 with Group VIIIB. Then continuing in the same direction the valence starts with 1 in Group IB and reaches a maximum of 7 in Group VIIA. The same general formulas for the oxides are found diametrically opposed on the spiral. Ifydrides. The elements fonning well-defined hydrides are located immediately to the right or left of the noble gases. In general the hydrides to the right, in Groups IA and IIA, are saltlike solids, while those to the left are nonpolar liquids or gases when dry. The singular role of hydrogen should again be noted. Considered as its own hydride, hydrogen bridges the polar and nonpolar hydrides. It can be observed that with a spiral arrangement of this type elements forming hydrides are all found in a confined area on the chart.' THE METALS AND NONMETALS
The nonmetals and metalloids are separated from the metals by the dotted lines. As in the case of the hydrides it will be seen that the nonmetals are confined to a limited area of the chart.
on a spiral chart than on the conventional tables or on the more recent ones where the elements are not arranged according to atomic numbers (2, 4, 6 ) . CONCLUSION
The term periodic table, or chart, means to most chemists a compact arrangement of the elements so ordered that they portray the periodic law. a law based on atomic numbers. That the properties of the elements are intimately bound with the number of outer electrons of the atom cannot be doubted. Nature built the atoms of the elements in an orderly way by increasing, from one element to the next, the number of electrons by one. Were the natural laws such that these newly added electrons all entered and remained in one shell the properties of the elements would be functions of the total number of electrons, hence direct functions of the atomic number. But the properties are periodic functions of the atomic numbers, and the reason for this fact is found in the periodic occurrence of similar outer orbital structures. If an arrangement of the elements is made according to the natural sequence of atomic numbers and the periodic occurrence of similar outer orbital configurations as well as the periodic occurrence of properties, it should faithfully reflect the periodic law. The spiral arrangement, as has been shown here, is capable of this reflection, and greater attention to truly continuous charts of the elements is urged as a means of discovering new relationships of the elements as well as a means of interpreting the periodic law. ACKNOWLEDGMENT
The author expresses his sincere thanks to Mr. John C. E. Taylor, Department of Art, Trinity College, for his interest and help in drawing the chart. LITERATURE CITED
(1)
CASWELL, "A new graphical arrangement of the periodic table," Phyr. Rm.. [2], 34, 543 (1929).
(2) EBLE."Atomic structure and the periodic table,"
RADIOACTIVITY
All of the naturally occurring radioactive elements are found along the outer loop of the spiral. To determine the end product of a radioactive series move clockwise two atomic numbers for each alpha particle lost (one number for each positive charge) and move counterclockwise one atomic number for, each beta particle lost. These changes are more easily followed
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The alloy type of hydride has not been considered here.
J. CHEM.
EDUC., 15, 575 (1938). (3) Gan~mn,"A table of electronic configurations of the ele-
,,
ments," Nature, 125, 146 (1930). periodic table," CHEm, 393 (1939); "Electronic configuration as the basis of the periodic table," ibid., 20, 21 (1943). (5) QUAM AND QUM, "Tmes of Paphic classifications of the elements," ibid., 11, 288 (1934). (6) VANRYSSELBERGHE, ,'A new periodic table." ibid., 12, 474 (1935). (7) Zm~czmsm,"Periodic system of the elements in a new form,'' Oid., 14, 232 (1937). (4) Lwen,
CORRECTION I N DR. HAUSER'S article in our January number, "Synthetic rubber and plastics," 700,000 long tons were
incorrectly translated into pounds. This conversion, in the 7th line, should have been "1,500,000,000 pounds."
