Introduction The new periodicity The comparison of the models Outlook Sources
Home The comparison of the models Discussion of both models

The comparison of the models


The quantum mechanical states The periodic table from Mendelejew and Meyer The Periodic Table by Bettermann Discussion of both models The quantum-mechanical shell model The gradient term Limits of Quantum Mechanics

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discussion of both models

The differences between the two models of order can be summarized in three points:

- The number of periods and the number of occupied states per period
- The nature of the formation period
- The occupation of the states and the periods

Number of periods and the number of occupied states during periods
The Mendelejewsche order of the elements is made up of seven periods. Motivation is the number of periods by the number of stable noble gases, and the following elements of the seventh period. The number of members is selected, the period to complete the noble gases, the periods. The periods have been formed which is a noble gas at the end of the period is.
In Bettermann's model is omitted, the noble gas at the end of the period, therefore, in this model are all stable elements shown in only six periods.
Manner of formation period
In Mendeleyev Periodic System, the periods are established by two fundamental principles, the periods begin with a Alkaliemetall and every period ends with a noble gas. This means that at each beginning of the period is an element with a valence electron and each period is completed by an element which has a closed shell. This principle ultimately leads to the incorrect assignment of the states and the exchange of the principal quantum numbers. The breakdown in the lower bowl is attributed to the quantum numbers l, m and s, which originate from a dynamic (the electrons move around the nucleus) model. The sub-shells d and f can be pushed between the s and p-shells of the individual periods.
In Bettermann's model, the periods and the sub-shells entirely of the coefficients of the polynomials are Lisitschinschen derived. The periods are constructed from polynomials similar slope characterized by the coefficient alfa. All neutral elements that belong to a group (like lead) of polynomials will be grouped in one period. The elements are lined up according to their atomic number in the periods.
The periods with its sub-shells in Bettermann's model comes completely without quantum numbers, the number of the size needed, the period counter is you n corresponds to the principal quantum number n of quantum mechanics..

The occupation of the states and the periods
The first two periods are the same in both models of the Periodic Table.

The third period is identical to the 18 element argon in both models. Thereafter, interest in Bettermann's first model, the downstream sub-shell with 10 elements in it almost corresponds to the 3d shell of the quantum mechanical model. There are the elements with atomic numbers 19 to 28 In Mendeleyev's model, they are assigned and arranged between the 4s and 4p subshell of the fourth period. With this reorganization, the Mendeleyev model, the first two elements of the 3d subshell are assigned to the 4s states, although they must be assigned to the 3d states, since they need to cater to the isoelectronic series, the principal quantum number n = third At the end of the pasted 3d states two elements are assigned to the 3d states, although they would have to occupy the 4s states. In the upstream sections of this effect has been described in detail.