2.6 Resonance and Formal Charge

• Resonance structures result from the delocalization
• How many resonance structures does benzene have?

  Two
• What must be consistent in all valid resonance structures regarding unpaired electrons?

  Their number
• Rules for drawing valid resonance structures

  1️⃣ Maintain the same atomic positions

  2️⃣ Maintain the same total number of bonds

  3️⃣ Maintain the same formal charge

  4️⃣ Maintain the same number of unpaired electrons
• The major resonance contributors are the most stable
• Match the resonance structure stability factors with their descriptions:

  Formal Charges ↔️ Structures with minimal formal charges are more stable

  Electronegativity ↔️ Most electronegative atoms should have negative formal charges

  Charge Separation ↔️ Fewer separated charges increase stability
• The formula for formal charge is: Valence electrons - Bonding electrons - Lone pair electrons.


  True
• Resonance occurs due to the delocalization of electrons.
• Electron delocalization in resonance structures spreads electrons over several bonds or atoms.


  True
• Electron delocalization in resonance structures involves the spreading of electrons over several bonds or atoms.


  True
• The number of unpaired electrons must be consistent in all resonance structures
• If formal charges are unavoidable, the most electronegative atoms should have negative formal charges.


  True
• The formula to calculate formal charge is: Formal charge = Valence electrons - Bonding electrons - Lone pair electrons
• Resonance enhances stability by spreading out electron density.

  True
• The atomic positions must remain constant across all resonance structures.

  True
• Electron delocalization in resonance structures refers to the spreading of electrons over several bonds
• The formal charge on each atom should be the same
• If formal charges are unavoidable, the most electronegative atoms should have negative formal charges
• The major contributors in resonance structures are the most stable representations of electron distribution.

  True
• The formal charges in H2O are all zero, indicating a neutral molecule.


  True
• Resonance structures differ in the positions of electrons
• The total number of bonds must be the same in each resonance structure
• The arrangement of atoms must remain constant across all resonance structures.


  True
• Major resonance contributors are the most stable resonance structures and contribute more to the hybrid structure.

  True
• In the ozone molecule (O3), one major resonance contributor has minimal formal charges
• Resonance theory predicts that bond lengths in molecules are intermediate between single and double bonds.


  True
• What does resonance refer to in chemistry?

  Multiple Lewis structures
• Resonance structures occur because electrons are not confined to specific bonds
• Resonance structures are drawn for molecules or ions with delocalized electrons.


  True
• The arrangement of atoms must remain constant
• Structures with minimal formal charges are more stable.


  True
• In the carbonate ion, the major resonance contributors have minimal formal charges
• In the water molecule (H2O), the formal charge on oxygen is zero
• Match the resonance concepts with their descriptions:

  Lewis Structures ↔️ Diagrams representing bonding within a molecule

  Delocalization ↔️ Spreading of electrons over several bonds or atoms
• The arrangement of atoms must remain constant across all resonance structures.


  True
• Atomic positions remain constant across all resonance structures
• Steps for drawing valid resonance structures

  1️⃣ Maintain constant atom arrangement

  2️⃣ Ensure equal bond number in each structure

  3️⃣ Keep formal charges the same

  4️⃣ Maintain consistent unpaired electrons
• Match the stability factors with their descriptions:

  Formal Charges ↔️ Minimal charges increase stability

  Electronegativity ↔️ Negative charge on most electronegative atom

  Charge Separation ↔️ Fewer separated charges enhance stability
• In the water molecule (H2O), the formal charge on oxygen is 0.

  True
• What remains constant across resonance structures of a molecule or ion?

  Atomic positions