Lecture 1 : Bonding concept s in main group chemistry
Example 2 : CO
Solution :
CO (carbon monoxide) Total number of electrons 4 + 6 = 10
Connect the two atoms with a pair of electrons as two dots and count the remaining electron pairs 10-2 = 8 electrons left
Complete the octet of oxygen atoms and count the remaining electron pairs 8-6 = 2 electrons
Place the remaining electron pair on carbon atom, All the electrons are utilized and octet is not satisfied for carbon as there is a shortage of four more electrons.
Drag two electron pairs on oxygen atom in between carbon and oxygen to establish two more bonds so that a triple bond exists between C and O which satisfies the octet of both C and O.
The structure is or or
Problems:
Work out Lewis structures for: BF4-, PCl3, PO43-, SO42-, O3, N2 and SO2
10-2 = 8 electrons left 
8-6 = 2 electrons
All the electrons are utilized and octet is not satisfied for carbon as there is a shortage of four more electrons.
Drag two electron pairs on oxygen atom in between carbon and oxygen to establish two more bonds so that a triple bond exists between C and O which satisfies the octet of both C and O.
or 
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