Question

The reason for chromium to have [Ar] 3d 4st configuration instead of [Ar]3d44s2 is
a)paulis exclusion principle
b)aufbau principle
c) heisenbergs principle
d)more exchange energy
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Answer 1

Answer:

According to Hund's rule, first we fill single electron in every orbit of a subshell then we go for next ,here all the D orbit get filled by single electron that show it follow the Hund's rule.