Molecular Orbital Theory:- Full Study

Introduction Molecular Orbital Theory :- 

Molecular orbital (MO) theory is used to explain bonding in molecules which was not explained by Valence Bond Theory . Molecular Orbital Theory is helpful to predict molecular properties such as , shape , magnetism and bond order .

It was initially given by Robert S. Mulikan and F. Hund in 1930 .

The main Points of Molecular Orbital Theory of covalent bonding :-

1. The electrons belonging to two bonding atoms are controlled by the entire molecule .
2. The electrons will occupy molecular orbitals that are analogous to atomic orbitals and these molecular orbitals belongs to the entire molecule .
3. There are s, p, d ... atomic orbitals are determined in atoms by various values of quantum numbers but in a molecule , we have a set of molecular orbitals called sigma , π, delta ... determined by various quantum numbers.
4. Molecular orbitals can accommodate only a maximum of two electrons just like atomic orbitals as per Pauli's exclusion principle.
5. An electron in an atomic orbital is inflused by 1 nucleous , but in molecular orbitals it is inflused by two or more nucleous , therefore atomic orbitals are non-centric but molecular orbitals are poly-centric .
6. The number of molecular orbitals formed is equal to the number of combining atomic orbitals.
7. When two atomic orbitals combines , two molecular orbitals are formed . One is known as bonding molecular orbital while the other is called anti-bonding molecular orbital .
8. The binding molecular orbital has lower energy hence greater stability than the corresponding anti-bonding molecular orbital .

Rules of Molecular Orbital Theory:

There are some principles below on which molecular orbital theory works -

1. The number of molecular orbitals produced is always equal to the number of atomic orbitals of the combined atoms .
2. Bonding molecular orbitals have lesser energy than the parent orbital while the antibondinv orbital have higher energy .
3. Electrons of the molecules are filled in orbitals from lower to successively higher energy levels.
4. When the atomic orbitals are of similar energies they combine to form molecular orbitals .

This was all about Molecular Orbital Theory , but there is one topic remaining i.e. filling of electrons in molecular orbitals which we will discuss in next article .

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