Crystal Field Theory
 

Can anyone explain why, specifically in regards to Crystal Field Theory, why the lattice energies and Hydration enthalpies going across group 1 of the transition metals are not linear, except when considering only d0, d5, and d10 metals?

Whoa. I have no idea. I'll try to look it up later.

I vaguely remember something about half filled, fully filled and empty subshells being more stable than otherwise. This might explain why a trend including d0, d5 and d10 metals might not include d6 or d3 metals. I haven't been able to locate that section of my textbook however.

I might be thinking of something entirely different - ionization energies or something...

Re: Crystal Field Theory
 

If your still searching for the answer

you'll need to consider the particular geometries of each complex of the transition metal with water e.g. how many ligands of water molecules are supported by each metal in a complex?