(a)
15. Electron configurations for the ions assuming a strong crystal field splitting (d-electron energy level splitting).
| (a) Y^3+ | Kr core | diamagnetic |
| (b) Pt^3+ | 5d^8 | paramagnetic |
| (c) Rh^3+ | 4d^6 | paramagnetic if strong splitting |
| (c') Rh^3+ | 4d^6 | diamagnetic if weak splitting |
| (d) V^2+ | 3d^3 | paramagnetic |
| (e) Ce^4+ | Xe core | diamagnetic |
| (f) U^4+ | 5f^2 | paramagnetic |
25. NH_4^+ because the proton, H^+, occupies the lone pair electrons of NH_3.
37.
(a)
(b) No isomers. The complex looks like 
(c) No geometrical isomers. The complex looks like 
(d) No geometrical isomers. The bidentate complex looks like 
39. Enantiomer means non-superimposable, mirror images. Only figure (b) with four different groups about the central carbon has a non-superimposable mirror image.
41. 
46. In both complexes Co has a valence of 3+ and is therefore d^6. [CoF_6]^3- must have a small crystal field splitting (the d-level energy separation must be small) and filling the five d-orbits with six electrons, following Hund's rule, gives a total electron spin S = 2.
The ammonia complex, being diamagnetic must have a strong d-level splitting so that the three lowest levels completely fill up with the six electrons and therefore S = 0.
49. Complex appearing violet must absorb yellowish light of around 580 nm.
61. For the NH_3 complex reaction the Gibbs Free Energy = -45 kJ/mol, Enthalpy = -109 kJ/mol and Entropy = 212 J/K
For the (en) complex reaction the Gibbs Free Energy = -102.7 kJ/mol, Enthalpy = -117 kJ/mol and Entropy = 48 J/K
It would appear that the great reduction in entropy going from the monodentate complex with ammonia to the bidentate complex with ethylene diamine offers great stability-a high formation constant. Biological complexes are most often bidentate or even higher so it must be that this is an evolutionary advantage living systems have used.