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.