Oxidation #s help


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kristinalaudis3e
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Oxidation #s help

Postby kristinalaudis3e » Tue Dec 15, 2020 8:04 pm

How oxidation numbers, I know that you would usually look at the number of ligands attached to the central Atom and based off their charges calculate the oxidation number of the whole molecule, but if there is an atom attached to the outside (so not the central atom), can you use only that atom to calculate the net charge of the whole molecule?

705383815
Posts: 101
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Re: Oxidation #s help

Postby 705383815 » Tue Dec 15, 2020 8:09 pm

I believe you would need to take the other molecules into consideration. I usually go about determining the charge of a molecule using the formal-charge analysis method for each atom and then adding the results.

Ruth Rosales 3D
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Re: Oxidation #s help

Postby Ruth Rosales 3D » Tue Dec 15, 2020 8:31 pm

Usually, I determine the oxidation number from the charge of the atom.

For example: MgCl2
Knowing that Cl = -1
Mg + 2Cl = 0
Mg + -2 = 0
Mg = +2

Hope this helps

Giselle Granda 3F
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Re: Oxidation #s help

Postby Giselle Granda 3F » Tue Dec 15, 2020 9:28 pm

So the overall charge of the coordination complex depends on what atom is on the outside of the brackets ( say it’s Cl which has a -1 charge, which then means the complex has an overall charge of +1). Then to find the oxidation number of the metal in the brackets, determine the charge of the ligands (taking into account how many of each ligand there is), and once determined subtract or add the charges of the ligands from/to the overall charge to get the oxidation state. Hope this helped!

Astha Patel 2J
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Re: Oxidation #s help

Postby Astha Patel 2J » Tue Dec 15, 2020 9:52 pm

To reiterate what others have said, you take the charge of the element that interacts with the complex ion (which is what is in brackets). The total charge of the compound should be zero, so you know that the charge on the element(s) outside of the brackets should equal the negative of the total charge of the ion. Then you add all the charges of the ligands up and you take the total charge of the ion and subtract the ligand charges. You'll be left with the charge of the central metal.

Izamary Marquez 2H
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Re: Oxidation #s help

Postby Izamary Marquez 2H » Tue Dec 15, 2020 9:59 pm

Ruth Rosales 3D wrote:Usually, I determine the oxidation number from the charge of the atom.

For example: MgCl2
Knowing that Cl = -1
Mg + 2Cl = 0
Mg + -2 = 0
Mg = +2

Hope this helps


Do we always assume that the oxidation for Cl is -1 because that's its more stable state?


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