Chromium has the electronic configuration `4s^1 3d^5` rather than `4s^2 3d^4` because

Options

A. Pauli's exclusion principle
B. Aufbau principle
C. Rule of half filled and completely filled orbitals
D. Heisenberg's uncertainty principle

Answer

C

Explanation

Hund's rule of maximum multiplicity is a rule based on observation of atomic spectra, which is used to predict the ground state of an atom or molecule with one or more open electronic shells. The rule states that for a given electron configuration, the lowest energy term is the one with the greatest value of spin multiplicity. This implies that if two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pairs. Hence a state of `3d^(5)4s^(1)` possesses higherspin multiplicity tha`3d^(4) 4s^(2)`