Multielectron Atoms and Electron Configurations

The connection between the Pauli exclusion principle and the more general Pauli principle can be understood as follows. If two electrons with the same spin a were to occupy the same orbital ip, the total wave function for the system would be written yi, zO (/ to, yi, 

Exchanging the coordinates of the two electrons changes the wave function to tlf(x2, yi, z2) Pa(x, yi, Zi), which is the same as before. Since the wave function does not change sign, it is forbidden by the Pauli principle. Hence two electrons with the same spin cannot be described by the same wave function, or, in other words, an orbital cannot contain two electrons with the same spin. As we shall see, this form of the Pauli principle is used in describing atoms and molecules in terms of orbitals. 

Period Number Element Configuration Period Number Element Configuration 

Period Atomic Number Element Electron Configuration Atomic Period Number Element Electron Configuration 

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Electron Spin and the Pauli Exclusion Principle Orbital Energy Levels in Multielectron Atoms Electron Configurations of Multielectron Atoms Electron Configurations and the Periodic Table... 

The observed ground-state electron configuration is always the one that gives the lowest total energy for the atom. As discussed in the text, electron motions in a multielectron atom are highly correlated consequently, the total energy of an atom is, in some cases, a very delicate balance between electron-nuclear attractions and electron-electron repulsions. 

The electron configuration for the molecule is obtained by placing the electrons into the MOs in a particular order. This is analogous to the conceptual model we used for multielectron atoms. The only difference here is that we are filling MOs, not AOs. Not surprisingly, rules we used for atoms, such as the Pauli exclusion principle and Hund s rule, also apply to molecules. That is, the maximum number of electrons per... 

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