Determining Oxidation [ENDORSED]

[ErinMae_Bacasen1L]

Name the following compound: [Co(en)2(CN)Cl]Cl
I tried doing number 2 in the workbook, quiz 3 prep fall 2014. Why does cobalt have an oxidation number of 3 when the charges of the other ions inside the brackets amount to -2? Does this mean we count the elements (in this case Cl) outside the brackets into determining the oxidation number?

[Claire Miller 3C]

The cation is neutrally charged the Chlorate anion has a charge of -1, the cyano ligand has a -1 charge, the ethylenediamine ligand is neutral, and the Chloride ligand has a -1 charge. These add up to -3 so to make the cation neutral the metal must have a charge of +3.

[Diana_Visco_1l]

Okay so...
(en)2 = 0 charge.
(CN) = -1 charge
(Cl) = -1 charge
(Cl) = -1 Charge.

By addition, you get: -1 + -1 + -1 = -3. The compound as a whole is not an ion (not a cation or anion)so it has a neutral charge of 0. In this case to make this compound 0, the metal has to have an oxidation number of 3 as seen below.
(3) + -3 = 0.