# Carbon-12 Ion

Gold Member
Hello;

What is the ionic formula for a carbon-12 ion? It has 4 electrons in its 2nd shell with a capacity of 4, so does that make it C4+ or C4-? I think that it is C4+, because in order for it to bond with the oxygen molecule, O2, it must be positive, as the oxygen ion is negative... is this reasoning correct?

Also, if I get carbon monoxide, CO, is that not CO2+? Because carbon has a charge of +4 and oxygen a charge of -2.

Thanks.

## Answers and Replies

Fermions83
To answer your question about the carbon monoxide, the carbon is triple bonded to the oxygen, giving the oxygen a formal charge of +1, and the carbon a formal charge of -1, the charges cancel (its neutral), that is why there is no ionic charge on a carbon monoxide molecule.
I am not sure what you mean by the carbon-12 ion problem. As far as I remember, carbon-12 simply means it is a carbon molecule with 6 protons and 6 neutrons, that is why it is called carbon-12, 6+6=12. You are partially correct in saying carbon has 4 electrons in its second shell, it actually has 4 electrons in its second energy level. In the second energy level, the first 2 electrons are in the S orbital, and the last 2 are in the P orbitals.
When carbon bonds with 2 oxygens, it is a similar story as to CO, except the oxygens are both double bonded to carbon, having no formal charges on any of the atoms, are all of there octets are satisfied.

mikelepore
CO is a molecule, not a polyatomic ion. To figure out the oxidation numbers of the C and O, you begin with the fact that O is -2, and you know that the total has to be zero for any molecule, therefore the oxidation number for C must be +2.

The oxidation number of carbon depends on formula. If it were carbon dioxide instead , we would have to begin with oxygen is -2, and you have two of them, making -4, and the total for the molecule has to be zero, therefore carbon is +4.