To add curved arrows to both resonance structures showing the delocalization of electron pairs needed to form the other resonance contributor, follow these guidelines based on the principles of electron movement in resonance:

How to Draw Curved Arrows for Resonance

• Curved arrows represent the movement of electron pairs (two electrons) between bonds or lone pairs. The tail of the arrow starts at the electron source (a lone pair or a pi bond), and the head points to where the electrons move (a bond or a lone pair)

• Types of electron movements in resonance:
  1. A lone pair forms a pi bond to an adjacent atom.
  2. A pi bond moves to form a new pi bond with an adjacent atom.
  3. A pi bond breaks to form a lone pair on an adjacent atom

• Do not add or remove electrons ; resonance structures must have the same number of electrons

• Formal charges shift accordingly : the atom losing electrons becomes more positive, and the atom gaining electrons becomes more negative

Applying Curved Arrows to Your Structures

1. Identify the electron pairs (lone pairs or pi bonds) that move to form the other resonance structure.
2. Draw a curved arrow from the electron pair that moves (for example, a lone pair on an oxygen or a pi bond between two atoms).
3. Draw a second arrow if needed to show the subsequent movement of electrons (for example, shifting a pi bond to another position to maintain octet rules).
4. Ensure arrows show electron flow only to adjacent atoms or bonds , consistent with resonance rules

5. Check that no atom exceeds the octet rule and that formal charges are conserved between resonance forms

Example (Generalized)

• If an oxygen lone pair moves to form a double bond with a carbon, draw a curved arrow from the oxygen lone pair to the oxygen-carbon bond.
• Simultaneously, draw a curved arrow from the carbon-carbon double bond to the adjacent carbon atom to show the pi electrons shifting.
• This sequence illustrates the delocalization of electrons that stabilizes the molecule through resonance

By following these steps and conventions, you can add the curved arrows to both resonance structures clearly showing the electron pair delocalization that interconverts them.