What is the oxidation number of carbon in the ion (Co3)2-?
The carbon is fully oxidized. Therefore, it is
The sum of the formal oxidation numbers in an a complex or compound ion must sum to the charge of the ion. Here the charge is
What is the oxidation number of carbon in oxalate ion,
The oxidation number of the carbon is +4.
Oxygen normally has an oxidation state of -2.
Oxygen = three ions each with a charge of -2 = 3 x -2 = -6
The overall charge of the polyatomic ion is -2
This means that the oxidation number of the carbon must be +4.
Total charge = +4 + -6 = -2
Video from: Noel Pauller
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