Periodic table the product of subjective human interpretation, contingent upon the circumstances, beliefs and predilections of human observers. An objective basis for chemical periodicity would settle the questions about the location of hydrogen and helium, and the composition of group 3. Such an underlying truth, if it exists, is thought to have not yet been discovered. In its absence, the many different forms of periodic table can be regarded as variations on the theme of chemical periodicity, each of which explores and emphasizes different aspects, properties, perspectives and relationships of and among the elements. Periodic table The periodic table, or periodic table
Extended periodic table due to its much higher atomic weight. Unseptbium should be a strong Lewis acid, forming fluorides and oxides, similarly to its lighter congener xenon. Because of this analogy of elements 165–172 to periods 2 and 3, Fricke et al. considered them to form a ninth period of the periodic table, while the eighth period was taken by them to end at the noble metal element 164. This ninth and final period would be similar to the second and third period in that it should have no transition metals. Immediately after element 172 (unseptbium, the last period 8 element), the first