Question

Define the following:-
(a) Hund's rule
(b) Afbau principal
(c) Pouli principal

Answer 1

A Hunds rule.  Hund's rule states that: Every orbital in a sublevel is singly occupied before any orbital is doubly occupied B.  The aufbau principle states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels Pauli.  The Pauli Exclusion Principle states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers