Sapling 6

[Karina Rodriguez 2H]

Give the oxidation state of the metal species in the complex [Co(NH₃)₄Cl₂]Cl. Can someone explain how to do this?

[Isaias Gomez D3A]

Well we know that Chlorine has a charge of -1 and there are 3 of them, giving us a charge of -3 from the Chlorines.
We also know that NH3 is neutral meaning it has a charge of 0.
If the whole compound has a neutral charge overall, that means Co must have a charge of +3 to cancel out the -3 from the the three chlorine atoms.

[Sonel Raj 3I]

I am not 100% sure if this if always true, and it might vary, but so far in this section I have seen that the oxidation number is the same as the charge of the ion. The compound as a whole has a neutral charge, and the Cl3 has a 3- charge, and since we know the NH3 ligand is neutral (there's a chart in the book which might be helpful!), the charge of the Co would be 3+, and therefore the oxidation number would also be 3+.

[Savannah Torella 1L]

To find the oxidation state of the metal, which is Co, you first have the recognize the charges of the other atoms. NH3 has no charge and each Cl has a -1 charge. Since the overall charge is zero, you can use the equation (0)= (Co charge)+(0)+(-2)+(-1). This gives the metal atom a +3 charge.