question_answer

The statements                                                [AIIMS 1982] (i)            In filling a group of orbitals of equal energy, it is energetically preferable to assign electrons to empty orbitals rather than pair them into a particular orbital. (ii)           When two electrons are placed in two different orbitals, energy is lower if the spins are parallelare valid for

A)                 Aufbau principle              

B)                 Hund's rule

C)                 Pauli's exclusion principle            

D)                 Uncertainty principle