PROPERTIES AND THE PERIODIC TABLE

for showing the tendencies by family and by group of common physical and chemical properties. One drawback to this fundamental presentation has been t...
1 downloads 0 Views 627KB Size
JOURNAL OF CHEMICAL EDUCATION

PROPERTIES AND THE PERIODIC TABLE RICHARD N. RHODA Lehish University, Bethlehem, Pennsylvania

A

1-p

construction of this chart NUMBER of investigators have presented certain will be of value to other inproperties of elements by use of the long form of the vestigators. The chart conperiodic table.'ez This device is an excellent method sisted of the lone form of for showing the tendencies by family and by group of the periodic tableywith two common physical and chemical properties. rows below for the lanthOne drawback to this fundamental presentation has anide and actinide series. been the lack of suitable forms or charts for the recordThe space for each element ing of such data. Another factor that has retarded the was a rectangle 1 inch wide use of such presentation has been the disregard by and 2 inches deep. These many investigators of the fact that compounds of the dimensions were chosen in elements exhibit similar characteristic trends by family order to provide adequate and by group. The historical prediction of properties space for entering data, at of elements by the properties of surrounding elements the same time keeping the before the element itself was isolated may also be used On. Elemnt-R.ctan.lo of size of the chart within reasin l i e sense for compounds of the elements. the Chart. A c t v d Size onable limits. The symbol Fundamental work concerning metallic formates in this laboratory led to an investigation of chemical and and atomic number of each element were placed in the physical properties of all of the formates reported in the proper rectangle in as fine print as possible, the remainliterature to this time. Tabulation of these data was ing space being free for additional data (see the figure) best done in periodic form; experience gained in the The rectangles for recording data in the chart were ruled off in several ways, depending on the type of data ' HAZLEHTIRST, T.H., AND F. J. FORNOPF, J. CEEM.EDUC.,20, collected. For data concerning a single property the 77-9 (1943). 'KLINGENBERG, J., AND L. SPRINGMAN, ibid., 29, 81 (1952). space was not ruled further; for multiple data such as

u

H

MAY, 1953

melting point, boiling point, solubility, and the existence of hydrates, the spaces were ruled into four horizontal sections as indicated in the figure. Adequate space is present on the chart, especially between berylLium and boron and magnesium and aluminum, for explanatory symbols and codes.

261

Copies of the various types of this presentation can be made quite cheaply by use of a reproduction method of the Ozalid type, or can be printed in pads for greater use. Adwnced undergraduate and graduate instruction, as well as fundamental research, can be greatly enhanced by the use of such charts.