Periodic table modern classification

The use of the older restricted version of the Pauli principle has persisted, however, and is routinely employed to develop the electronic version of the periodic table. Modern chemistry appears to be committing two mistakes. Firstly, there is a rejection of the classical chemical heritage whereby the classification of elements is based on the accumulation of data on the properties and reactions of elements. Secondly, modem chemistry looks to physics with reverence and the false assumption that therein lies the underlying explanation to all of chemistry. Chemistry in common with all other branches of science appears to have succumbed to the prevailing tendency that attempts to reduce everything to physics (11). In the case of the Pauli principle, chemists frequently fall short of a full understanding of the subject matter, and... 

The chemistry of an element is determined by the manner in which its electrons are arranged in the atom. Such arrangements are the basis of the modern periodic classification of the elements the Periodic Table. 

The classification of elements in the Periodic Table is one of the greatest contributions made to modern chemistry. Today s improved Periodic Table positions the elements in order of atomic number rather than atomic weight because scientists have realized that, and to some extent why, the properties of elements depend on their atomic number (which gives us the number and arrangements of the electrons in their atoms). 

In this section, the principles described in previous sections are applied to the electronic configurations of all the elements, and this leads to a rationalization of the modern form of the periodic classification of the elements. The modern form of the Periodic Table is shown in Figure 3.4. 

Interestingly, this corresponds lo modern thinking on classification of the elements contrary to the vast majority of published periodic tables in which lutetium is wrongly shown as the last of the rare earths. W. B. Jensen, The positions of Lanthanum (Actinium) and Lutetium (Lawrencium) in the Periodic Table , Journal of Chemical Education, 59 (1982), 634-6. 

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