Lot of Conceptual and Theoretical Questions/Doubts from Inorganic Chemistry

7. Nitrogen has no vacant d-orbitals. It catenates but not as easily as phosphorus. So technically that honour should go to P. Tendency to catenate decreases down the group.
P > N > As > Sb > Bi though I'm not sure...haven't revised p-block.

8. That must be the average oxidation state. Or you may be referring to the solid state of N₂O₅, which exists technically as nitronium nitrate.

9. See, electron gain enthalpy and electron affinity are two different quantities if you were confused about them. They're related, in that
-(EGE) = EA
Electron gain enthalpy of noble gases is +ve, so EA is -ve meaning they have no affinity for electrons.

6. Yes, though weaker than carbon. An example is N₂.

1. H₂O₂ is an amphoteric oxide...looked this up.

2. Bhai how are lithium salts insoluble in water at all?? Isn't lithium cation supposed to have high hydration enthalpy? I think all of them are soluble in water..

pritish is rite i also thnk that all of them are soluble in water.. same reason me too as mentioned in JD Lee.
solubility decreases while descending a group.
but execptions are fluorides and hydroxides for whom solubility increases descending a group as for fluorides and hydroxides lattice energy decreases more rapidly than hydration energy which is reverse in case of others.
More over for solubility Hydration energy > Lattice Energy ( should be greater )

1) for this i scanned through JD lee and found H₂O₂ is a dibasic acid.

1.H2O2 is acidic as it turns blue litmus red. 2. LiNO3 is soluble. 8.Well, N2O5 is actually NO₂⁺NO₃^-