Achieve Homework #5, Question #6

[trishaferrer]

Hi! How would you solve for oxidation states such as in this problem?

[Meghan Spoeri 2D]

hi! For this problem, you would first have to identify the metal species in the compound because that is the oxidation number you are trying to determine. So in this case, you would be solving for the oxidation state of Co. First, determine the charge on the outside of the bracket: since there are 2 chlorine and each has a negative one charge, the overall charge outside the brackets would be -2. Therefore, the charge on the inside of the brackets must also be -2 since the overall charge is 0. On the inside of the brackets, there is one chlorine, so that has a charge of -1 and 5 NH3, which each have a charge of 0. Therefore, Co must have a charge of +3 because 3-1 = 2 and you need the inside brackets to have a charge of +2. hope this helps!

[RossLechner3E]

When finding oxidation number, I like to start by breaking down the induvial charges of everything inside the brackets. We have NH3 and Cl, we know NH3 will be neutral and have a charge of 0, however, Cl will be -1, and we have 2 so we know inside the brackets we have -2. Then looking outside, we see one additional Cl, this brings the total of the compound to -3, we know the compound must net 0 so therefore Co has to be +3, thus netting the entire compound zero.

[Jennifer Fuentes 2K]

hi for example give the oxidation state of the metal species in the complex [Co(NH3)5Cl]Cl . Let the oxidation state of Co be x

Oxidation state of NH3=0

Oxidation state of Cl=-1

So x+5(0)+2(-1)=0

x-2=0

x=2

So oxidation state of Co is +2

[Molly McAndrew 1 1H]

How do we know that the 5 NH₃ molecules will be neutral (i.e. charge of 0)?

[Darlene Luu 1H]

How do we know that the 5 NH₃ molecules will be neutral (i.e. charge of 0)?

Hi Molly! What helped me was using the PDF called "Naming Coordination Compounds" on Professor's class website. NH3 is under the category of neutral ligands.