Summary of Curly arrow:-
1. A curly arrow show the movement of a pair of electrons.
2. The tail of the arrow show the source of the election pair, which will be a filled orbital ( HOMO ) and can be represented by:
- a lone pair
- or a negative charge
- or a pie bond
- or a Sigma bond
3. The head of the arrow indicates the destination of the election pair, which will be:-
- an empty atomic orbitals where a new bond will be formed.
- or a Sigma antibonding or pie antibonding orbitals where a new bond will be formed and an old bond will break.
- or an electronegative atoms that can support a negative charge.
4. Overall change is always conserved in a reaction.
Note :- B, C , N, and O never have more than four bonds. If you make a new bond to uncharged H, C , N or O you must also break one of the existing bonds in the same step.
