How to find the Oxidation Number for C in CO2 (Carbon dioxide)

To find the correct oxidations number for CO2 (Carbon dioxide), and each element in the molecule, we use a few rules and some simple math.

First, since the CO2 molecule doesn’t have an overall charge (like NO3- or H3O+) we could say that the total of the oxidation numbers for CO2 will be zero since it is a neutral molecule.

We write the oxidation number (O.N.) for elements that we know and use these to figure out oxidation number for C.

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GENERAL RULES
In a netural molecule all Oxidation numbers must add up to zero.
Group 1 = +1
Group 2 = +2
Hydrogen with Non-Metals = +1
Hydrogen with Metals (or Boron) = -1
Fluorine = -1
Oxygen = -2 (except in H2O2 or with Fluorine)
Group 17(7A) = -1 except with Oxygen and other halogens lower in the group
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We know that Oxygen usually is -2 with a few exceptions. When Oxygen is in a peroxide, like H2O2 (Hydrogen peroxide), it has a charge of -1. When it is bonded to Fluorine (F) it has an oxidation number of +2.

Here it is bonded to element symbol so the oxidation number on Oxygen is -2. Using this information we can figure out the oxidation number for the element C in CO2.

[rebeccamenezes]

Not gonna lie, this is probably a very simple concept, but you taught it well and know I understand it. Great job!

[aishahramli]

Your explanation is so simple. Its easy to understand. I've watched lots of your video. Love this channel 👍

[evaz]

Thanks so much! This was such a simple and good explanation

[meowmeow]

Omg thank you sooo much ...u made my day better 💃

[silvrie]

but how do you know if its a nuetral molecule rather than a polyatomic one? (sorry im having a hard time understanding the methods)

[yashvardhanbharadwaj]

But Oxidation Number of O2 is always zero, it's written in my textbook NCERT