Metal complexes help

Question

1. Arrange the complexes in order of decreasing stability

A. Mg(OH)2

B. [Mg(H2NCH2CH2NH2)]2

C. [Mg(EDTA)]2-

I have tried A,B,C A,C,B and that is not right

2. Which of the following metal ions is most likely to exist as a stable eight-coordinate complex with fluoride?

A. Cu2

B. Cu

C. Fe3

D. Ag3

E. U4

I know B is wrong but i cant figure out what would be right

Answer 1

I would think the EDTA complex would be the most stable.  EDTA is used to chelate some toxins and remove them from the body.

Try C A B

As for #2, a coordination number of 8 is fairly unusual, but a general guideline is that the coordination number can be 2 times the oxidation number.  I'm thinking U4+ might be it.