Explain aufbau principle pauli's exclusion principle harsh rule of maximum multiplicity
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Answer:
Step-by-step explanation:
AUFBAU PRINCIPLE : Aufbau is a german term which means building up.
It states that the filling of electron in an orbital from lower enrgy levels to the higher energy levels.
Electrons will be filled as :
1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f, 5d,6p,7s,5f,6d,7p
PAULI EXCLUSION PRINCIPLE :
The Pauli Exclusion Principle states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins. This means if one is assigned an up-spin ( +1/2), the other must be down-spin (-1/2).
HUND'S RULE OF MAXIMUM MULTIPLICITY :
Hund's rule states that:
1.Every orbital in a sublevel is singly occupied before any orbital is doubly occupied.
2.All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).
When assigning electrons to orbitals, an electron first seeks to fill all the orbitals with similar energy (also referred to as degenerate orbitals) before pairing with another electron in a half-filled orbital. Atoms at ground states tend to have as many unpaired electrons as possible.