BONDING--A PRACTICAL APPROACH

Mostly for atoms in the first (n=1) and second (n=2) periods

(resonance structures not included)

Please add your own notes and examples.

ATOM	Valence/ e’s Needed	Bonding?	Bonding?	Lone pairs?	Formal Charge?
H	1 1 more needed	One single bond -H	No multiple bonds	Never!	Zero
F (Cl, Br, I)	7 1 more needed	One single bond -F	No multiple bonds	Three	Zero
O (S)	6 2 more needed	2 single bonds -O- FC = 0	1 double bond =O FC = 0	Two	Single bond and 3 lone pairs for O^- FC = -1
N	5 3 more needed	3 single bonds and 1 lone pair	1 single and 1 double with 1 lone pair	1 triple bond with a lone pair	1 lone pair, FC = 0
N+		4 single bonds, FC = +1	1 triple and 1 single bond, FC = +1	2 double bonds, FC = +1	0 lone pairs FC = +1
C	4 4 more needed	4 single bonds	2 single and 1 double bond	Never! (except CO)	FC = 0 (almost always)
C		2 double bonds	1 triple and 1 single bond		FC = 0