I have few queries - plz help 1. Anhydrous AlCl3 is covalent while AlCl3,6H2O is ionic - why? 2.CO and N2 are isoelectronic, but differ in donor properties -explain 3.Account for the decrease of I1 between P and S 4. What is Inner Metallic complex (please suggest a good text available in net) 5.Electron affinity of Cl is greater than F. yet F is much stronger oxidant than Cl -explain 6. The atomic radii of Zn and HF are almost same -why?

							
Dear Ashish ,
1.) In Anhyd. ALCL3 , since al^3+ ion is small and has high positive charge (=+3) , this ion has high polarising power and hence polarises Cl^-1 ion strongly.Due to high polarisation cl^-1 ion ion by Al^3+ ion, covalent charscter is produced in AlCl3.Hydrated salt is alcl3.6H2o which is obtained by dissolving anhydrous ALCL3 in H2o(polar solvent).In the formation of alcl3.6H20 ,alcl3 gets hydrated by water molecules and a large amount of hydration energy is also released.This hydration energy helps in the ionisation of hydrated salt alcl3.6h20 to give [Al(h20)6]^3+ and cl^1- ions.Reaction innvolved is :
Alcl3+6h20 ---> Alcl3.6h20 ---> [Al(h20)6}]^3+ + 3cl^1- + hydration energy  							
2.)  CO and N2 are isoelectronic because each have 2 nuclei and 10 valence electrons (4+6, 5+5respectively).They have different donor particles because in N2 there are two lone pairs on them while in case of CO there is only one lone pair .This can be also said in terms of electronegativity of N and O as N is more electronegative than O.