The penetration of the valence electron orbitals of the alkali metals into their inner shells and its effect on the energy levels can be considered through two methods that take into account modifications of the hydrogen formula (one-electron system). One of them considers the quantum defect, modifying the quantum number n; the other considers the effective nuclear charge Z* replacing the nuclear charge Z. The method using the quantum defect is widely used because this quantity is practically constant for a given angular momentum quantum number l. However, the method using effective nuclear charge is more realistic because it explains many atomic and molecular properties - but the effective nuclear charge depends on l as well as on the principal quantum number n. This article describes a relatively simple graphical procedure to calculate the effective nuclear charges experienced by the sodium valence electron from its atomic spectrum. A relation of Z* with n for a given l is obtained and the Z* values for all states of the valence electron are found; the energy terms can also be determined. The calculations can be performed by using common spreadsheet software.
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Citation
Sala, Oswaldo; Araki, Koiti; Noda, L. K. J. Chem. Educ.1999 76 1269.
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