Understanding Bond Length
* Bond Order: The higher the bond order (the number of bonds between two atoms), the shorter the bond length. A single bond is weaker and longer than a double bond, and a double bond is weaker and longer than a triple bond.
* Hybridization: Hybridization can also affect bond length. More s-character in the hybrid orbitals leads to shorter bonds.
Analyzing the Compounds
* H₂NNH₂ (Hydrazine): This molecule has a single N-N bond (bond order = 1).
* HNNH (Diazene): This molecule has a double N-N bond (bond order = 2).
Conclusion
Since HNNH has a double bond between the nitrogen atoms, it has a shorter N-N bond than H₂NNH₂ which has a single bond.
