IRON PERIODIC TABLE SERIES

Technetium (Tc), the element which belongs between ruthenium and molybdenum (Mo) has no stable isotopes and was not synthesized until 1937. It belongs between ruthenium (Ru) and palladium (Pd). This original prediction was actually borne out in 1923 with the discovery of hafnium. His later tables erroneously placed lanthanum in this spot. Mendeleev soon retreated from this prediction of a heavier analogue of titanium and zirconium. This table contains several implicit predictions of unknown elements. Mendeleev would use the latter sort of layout before long. Note also the cosmetic difference between Mendeleev's layout and that of modern tables, which order the elements in horizontal rows such that families of elements appear in vertical columns.

IRON PERIODIC TABLE SERIES

Notes The principle of periodicity is apparent in this first sentence: repetition of chemical properties in a series of elements arranged by atomic weight. Thus Bo (?) appears as an analogue of Bo and Al, as is well known to have been long established experimentally.

From the above table, some new analogies between elements are revealed.

A few atomic weights will probably require correction for example Te cannot have the atomic weight 128, but rather 123-126.

One can predict the discovery of many new elements, for example analogues of Si and Al with atomic weights of 65-75.

Thus the compounds of S and Tl, Cl and J, display not only analogies, but also striking differences. Therefore, in the study of compounds, not only the quantities and properties of the elements and their reciprocal behavior is to be taken into consideration, but also the atomic weight of the elements.

The magnitude of the atomic weight determines the properties of the element.

They are, therefore, the representative elements and so the lightest element H is rightly chosen as the most representative.

The elements distributed most widely in nature have small atomic weights, and all such elements are marked by the distinctness of their behavior.

The arrangement according to atomic weight corresponds to the valence of the element and to a certain extent the difference in chemical behavior, for example Li, Be, B, C, N, O, F.

Chemically analogous elements have either similar atomic weights (Pt, Ir, Os), or weights which increase by equal increments (K, Rb, Cs).

The elements, if arranged according to their atomic weights, exhibit an evident stepwise variation of properties.

Mendelejeff, Zeitschrift für Chemie 12, 405-406 (1869) translation by Carmen Giuntaīy ordering the elements according to increasing atomic weight in vertical rows so that the horizontal rows contain analogous elements, still ordered by increasing atomic weight, one obtains the following arrangement, from which a few general conclusions may be derived. On the Relationship of the Properties of the Elements to their Atomic Weights D. An English translation of that German abstract is presented here. The German abstract was the vehicle by which Mendeleev's ideas reached chemists working in Western Europe. That same year, a German abstract of the paper, consisting of the table and eight comments, was published in Zeitschrift für Chemie.

) The paper was published in the first volume of the new society's journal. (Actually, Mendeleev was ill, and his colleague Nikolai Menshutkin presented his paper. This table and the accompanying observations were first presented to the Russian Chemical Society in March 1869. As noted below, Mendeleev himself corrected some of the errors within a few years others persisted well into the 20 th century. Scientists, even great scientists, trying to see further than others have in the past, do not always see the whole picture clearly. Mendeleev's formulation was clearly superior in several respects to the work of contemporary classifiers: it was the clearest, most consistent, and most systematic formulation, and Mendeleev made several testable predictions based on it. Mendeleev was one of a number of independent discoverers of the periodic law in the 1860s-that number ranging from one to six depending on the criteria one adopts.

His chief contribution to chemistry was the establishment of the periodic system of elements. Mendeleev's First Periodic Table Elements and Atoms: Chapter 12ĭmitrii Mendeleev (1834-1907 see portrait of Mendeleev in 1878 by Kramskoy) was born in Tobolsk, in Western Siberia.

Iron periodic table