Where does co3 2- get its charge from

why does co3 have a negative 2 charge on it ? what does it symbolize?
please explain in detail, as i am very confused.
Thanx in advance :)

The two electrons on a carbonate ion that give it its negative 2 charge came from the one or two elements that were originally bonded to carbonate. The 2- indicates the electrostatic charge on the ion as a result of gaining electrons. A positive charge indicates that electrons are lost so that there are more positive charges in the nucleus than electrons around it. Metals form ions with positive charges. Nonmetals and polyatomic ions generally have negative charges.

Consider the case where sodium carbonate, Na2CO3, is dissolved in water. The action of the water molecules breaks the bonds between sodium and oxygen. But, since the oxygen is much more electronegative than sodium and since the bonding pair of electrons was drawn closer to oxygen, oxygen keeps the bonding pair of electrons giving it a net gain of one electron from one sodium atom. When this is repeated with the other sodium atom the resulting carbonate ion has gained two electrons, giving it a charge of 2-.

========== Follow up ===========

I'm sorry to have to say that Back's explanation is completely without merit. Carbon doesn't take away electrons for other atoms. Carbon shares electrons. Oxygen also shares electrons, but has a greater tendency to attract shared electrons than does carbon. This is why oxygen is assigned a greater electronegativity than is assigned to carbon. Therefore, when carbon bonds with oxygen in the carbonate ion the bonding pairs of electrons form a polar covalent bond. But that doesn't account for the two extra electrons. Those come from whatever other elements was in the compound before it split up to form ions, including the carbonate ion.

ok here is how it is. CO3 2- is a radical and we want to know how it got its negative charge of 2. Remember that the negative charge up there is as a result of the sum of the oxidation numbers of the constituents of that radical CO3 2-. So for this case, we know that oxygen always has an oxidation state of -2 except in peroxide where it is -1. So since we have the oxidation state of oxygen, we have to get the oxidation state of carbon. The highest oxidation state of carbon is +4 because of its position in the periodic table (4th group). It can also attain other oxidation states depending on the compound involved. So in this radical, oxygen has a -6 charge and the highest charge of carbon which is +4 is still not enough to nullify the -6 charge of oxygen. That is why we still have that -2 charge still hanging up there. Hope that helps.

carbon can take 4 electrons form any other element on the other hand each O can give away 2 electrons . on CO3 2- there are 3 O and one carbon so . there are 2 extra electron which makes it an CO3 2- ion. hope you understand it .

i am very confused