Conclusion
In this study, we have mainly tried to look the periodic table from the
Barut’s point of view and discussed the deviations from the Madelung
rule [4, 5]. This deviation is expected due to the reason called
spin correlation effect which is mainly related to the Hund’s first
rule. As explained in the calculation section the expected, observed and
computed total energies (Hartree-Fock and Gaussian) are given for two
different (one for expected and the other one is observed)
configurations of the Cr atom. Our results and the results calculated by
other researcher showed that the preferred electronic configuration for
the Cr is 4s13d5 not
4s23d4 as dictated by the Madelung
rule. This event may be due to the spin correlation effect which is
closely related to the Hund’s rule.