Quantum Mechanics and the Periodic Table

Let us start at an elementary level or with a typically "chemical" view. Suppose we ask an undergraduate chemistry student how quantum mechanics explains the periodic table. If the student has been going to classes and reading her book she will respond that the number of outer-shell electrons determines, broadly speaking, which elements share a common group in the periodic table. The student might possibly also add that the number of outer-shell electrons causes elements to behave in a particular manner. 

Whereas most chemists and educators seem to believe that all is well, I think that there is some benefit in pursuing the question of how much is strictly explained from the theory. It is indeed something of a miracle that quantum mechanics explains the periodic table to the... 

It Is something of a miracle that quantum mechanics explains the periodic table to the extent that It does we should not let this fact seduce us into believing that It Is a deductive explanation. Attempts to explain the details of the periodic table continue to challenge the Ingenuity of quantum physicists and quantum chemists, and the periodic table will continue to present a test case for the adequacy of new methods developed in quantum chemistry. 

Not everybody agrees with this claim, however. See B. Friedrich.. . Hasn t It A commentary on Eric Scerri s Paper, Has Quantum Mechanics Explained the Periodic Table Foundations of Chemistry, 6,117—132,2004 V.N. Ostrovsky, What and How Physics Contributes to Understanding the Periodic Law, Foundations of Chemistry, 3, 145—181,2001. 

The Periodic Table of The Chemical Elements (Table 2.3) was first organized by Mendeleyeff in 1869 [7] well before quantum mechanics and the modem theory of atomic structure, by using group analogies in chemical and physical properties Mendeleyeff even predicted two as yet undiscovered elements (Ga, Ge) and left spaces for them in his table. 

The Quantum-Mechanical Model and the Periodic Table Bulding Up Periods 1 and 2 Buiding Up Period 3 Section Configurations Within Groups Building Up Period 4... 

Pauli, Wolfgang (1900-58) Austrian-born Swiss theoretical physicist. Pauli is best known for his enunciation of the Pauli exclusion principle in 1925. This enabled the electronic structure of atoms to be understood, particularly how the shell structure of atoms, and hence the periodic table of the elements, comes about. Pauli won the 1945 Nobel Prize for physics for this work. Pauli made many other important contributions to physics including his prediction of the neutrino in beta decay, the incorporation of spin into quantum mechanics, and the explanation of paramagnetism in metals. He also wrote several classic books and reviews on quantum mechanics. 

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