Sapling #6

[Joshua Swift]

In this sapling question, it asks to give the oxidation state of the metal species in the complex [Co(NH3)5Cl]Cl
The answer turns out to be +2 but I am not too sure why. Any help?

[Leo Naylor 2F]

The oxidation state is +2 because the overall charge of the molecule is neutral, and you know each chlorine atom has a charge of -1, so since there are two chlorine atoms, the charge of the cobalt must be +2 to result in a neutrally charged molecule.

[Kaylee Messick 3J]

The way I think of it is the charge of the compound inside the brackets has to equal the opposite of the atom outside the brackets. Since the chlorine atom has a charge of -1, the charge of the atoms inside the brackets must be +1. This means since the chlorine inside the brackets is -1, the cobalt must be +2 because 2 + (-1) = +1 which cancels out the -1 charge of the chlorine. Hope this helps!

[Carolina 3E]

The coordination sphere has an overall charge of +1 since the oxidation state of Cl (outside) is -1 and the entire unit is neutral. The oxidation state of NH3 is 0 and the oxidation number of Cl (inside) is -1 and there is only one Cl within the coordination sphere so the oxidation state of Co must be +2.