Specify the oxidation numbers of the metals in the following coordination entities:
(i). `[Co(H_2O)(CN)(en)_2]^(2+)`
(ii). `[CoBr_2(en)_2]^(o+)`
(iii). `[PtCl_4]^(2-)` (iv). `K_3[Fe(CN)_6]`
(v). `[Cr(NH_3)_3Cl_3]`

Explanation

(i)`[Co(H_(2)O)(CN)(en)_(2)]^(2+) x+0+(-1)+0=+2`
(ii) `[CoBr_(2)(en_(2))]^(+) x=+3`
(iii) `]PtCl_(4)]^(2-) x-4=-2 x=+2`
(iv) `K_(3)[Fe(CN_(6)] 3+x+6(-1)=0 x=+3`
(v) `[Cr(NH_(3))_(3)Cl_(3)] x+0+3(-1)=0 x=+3`