The following coordination complexes are provided:
1. na[fe(oh)4
2. mg[cr(h2o)sbr]
3. cr(nh3)3cl3
4. pt(en)cl2
5. calcium hexabromoplatinate(iv)
6. hexacarbonylmanganese(i) perchlorate
7.ammonium tetrachlororuthenate(lli)
8. tris(ethylenediamine)copper(ii) sulfate

a) propose and draw plausible complex structures.
b) indicate which structures can exhibit configurational or stereo-isomerism and draw corresponding stereoisomers.
c) determine the electron count for each complex.
d) determine the formal charge of the metal and the number of d electrons