PAULLI’S EXCLUSION PRINCIPLE, EXPLANATION, Electron while moving around the nucleus also have another kind of revolutions, HUND’S RULE

 

The arrows   shoe the filling of electrons. Hence  the order comes for filling of electron is similar as derived from (n + l) value 15, 25, 2p, 35, 3p, 45, 3d, 4p, 55, 4d, 5p,65, 4f, 5d, 6p, 73, 5f, 6d, 7p,  6f, 7d and 7f.

 RULE 2: PAULLI’S EXCLUSION PRINCIPLE

             An orbital cannot hold more the two electrons. In case of two electrons one orbital, both the electrons must  have opposite spin which is also called pauli spin.

 EXPLANATION:

            Electron while moving around the nucleus also have another kind of revolutions about its axis which is called spin of electron. Spin is related with magnetic properties of an element.

In an orbital two electrons with same spin with procedure such an unstable system that similar magnetic line of force repeat each other and make this combination impossible. In case of opposite spin, one is moving clock-wise while other is moving anticlockwise. Hence, due to opposite magnetic lines produced due to opposite spin, they attract each other and minimize the repulsion between negatively charged two electrons to stay in on orbital but with opposite spin.

 

RULES 3: HUND’S RULE:- 

           

            This rule state that if degenerate orbitals of a subshell are available then electrons prefer to occur separate orbital with parallel (similar) spin instead of pairing of electrons with opposite spin. Electrons prefer to occupy separate degenerate orbitals with parallel spin because in this way electrons stay far apart from each other and it minimize the electronic repulsion but it increase the magnetic behavior of such an element due to un-paised electrons with similar spin.

 

EXAMPLE:

            Nitrogen:        E=7, P=7 and N=7, ¹⁴N = 15², 25², 2P³.

            Or                    1S^1v, 2^1v, 2px¹, 2py¹, 2pz¹

            Sometimes electronic configuration is represented in box form:

1

1

1

1v

1v

            N = 

                            15          25                 2p

 

Argow:  Ar

 

Ar = 15², 25², 2p⁶, 35², 3p⁶

 

            Scandium,  5c