Assign formal charges to each atom in the three resonance forms of N2O

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Assign formal charges to each atom in the three resonance forms of N2O. :N-N=0: •N=N-0: A :Z: :2: N=N=0 Which resonance structure contributes the most to the overall structure of N2O? :N?N=0: N=N=0 N=Ö :N=N-0: -4 -1 +2 Answer Bank -3 0 +3 -2 +1 +4 ResourceAssign formal charges to each atom in the three resonance forms of N2O. :N-N=0: •N=N-0: A :Z: :2: N=N=0 Which resonance structure contributes the most to the overall structure of N2O? :N?N=0: N=N=0 N=Ö :N=N-0: -4 -1 +2 Answer Bank -3 0 +3 -2 +1 +4 Resource

The Correct Answer and Explanation is :

Assigning Formal Charges to Each Resonance Structure of ( N_2O ):

To determine the formal charges, we use the formula:

[
\text{Formal Charge} = (\text{Valence Electrons}) – (\text{Nonbonding Electrons}) – \frac{(\text{Bonding Electrons})}{2}
]

Resonance Structure 1: ( :N-N=O: )

  • Left N (terminal): ( 5 – 4 – \frac{4}{2} = 5 – 4 – 2 = -1 )
  • Middle N: ( 5 – 0 – \frac{8}{2} = 5 – 0 – 4 = +1 )
  • Right O: ( 6 – 4 – \frac{4}{2} = 6 – 4 – 2 = 0 )

Formal charges:
[ (-1) + (+1) + (0) ]

Resonance Structure 2: ( \cdot N=N^+-O^- )

  • Left N (terminal): ( 5 – 3 – \frac{4}{2} = 5 – 3 – 2 = 0 )
  • Middle N: ( 5 – 0 – \frac{8}{2} = 5 – 0 – 4 = +1 )
  • Right O: ( 6 – 6 – \frac{2}{2} = 6 – 6 – 1 = -1 )

Formal charges:
[ (0) + (+1) + (-1) ]

Resonance Structure 3: ( :N=N=O: )

  • Left N (terminal): ( 5 – 2 – \frac{6}{2} = 5 – 2 – 3 = 0 )
  • Middle N: ( 5 – 2 – \frac{6}{2} = 5 – 2 – 3 = 0 )
  • Right O: ( 6 – 4 – \frac{4}{2} = 6 – 4 – 2 = 0 )

Formal charges:
[ (0) + (0) + (0) ]

Which Resonance Structure Contributes the Most?

The third resonance structure ( :N=N=O: ) contributes the most to the overall structure because:

  1. It has the least formal charge separation, meaning it is the most stable.
  2. It follows the octet rule for all atoms.
  3. Nitrogen is less electronegative than oxygen, so if there were a negative formal charge, it would prefer to be on oxygen rather than nitrogen. This favors the second structure slightly, but since the third has all formal charges at zero, it is the most significant contributor.

Thus, the major contributing resonance structure is ( :N=N=O: ) with all formal charges equal to zero.

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