IMPORTANT POINTS FOR MCQS

Molecular Orbital Theory (MOT)

            This theory was presented by Hund and Mulikan.

1;  According to this theory when two atomic orbitals overlapped, they form two molecular orbitals.

2; One of them is of low energy and the other is of high energy.

3; Lower energy molecular orbital is called Bonding molecular orbital and is represented by s & p,

4;Bonding molecular orbital is formed, when atomic orbitals attract or reinforced each other.

5;Anti bonding M.O is formed, when atomic orbital cancelled or repelled each other.

6; Energy of B.M.O is least, when the combining A.O has equal energy.

7;The number of bonds formed (single, double or triple) can be determined by term called Bond Order. 

Bond order = No. of pair of electrons in bonding molecular orbitals – No. of pair of electrons in anti-bonding molecular orbital.

8; Magnetic character of oxygen and other compounds can be explained by M.O.T. 

Bond order ;= number of pair of electrons in BMO  -  number of pair of electrons in anti BMO

            OR B.O = 4 -2 = 2 or double bond is present i.e. O=O

            Paramagnetism:-        The phenomena in which a substance is attracted by a magnetic         field     called             paramagnetism.  Paramagnetism is due to the presence of unpaired es.

            Diamagetism:-            The substances which are not affected by magnet, called        diamagnetic     substance.              Such substances have no unpaired electrons.