I have a compound of Na2subscriptCO3subscript. The cation it breaks into is NA+1 in the upper righthand corner, and the anion is CO3subscript,-2in the upper right hand corner. Where did the anion numbers come from? How can you tell what the charge is? I know you either look in the periodic table square, or at the top of the periodic column, but I don't see where the charge of -2 comes from since carbon is in the +4 column. Thanks for clarifying this.
Na has a +1 charge because its in the first group of the periodic table. For the CO3, didn't the teacher give you a sheet of common ions that tells you what the charges are? That was what my teacher did. But if you don't have the sheet, I THINK the reason why it has a -2 charge is because of the oxygen. If do not do anything with the C.
Chopsticks is right. Usually you memorize a set of common anions. Here is a link to a set that includes more than just the common ones.
(Broken Link Removed)
But in your case, it is far easier to do it another way. Sodium carbonate is Na2CO3. You know Na is +1 and two of them make a total of +2 on the Na. Since every compound is neutral, you KNOW the remainder is -2 (the carbonate or CO3). If you wanted to determine C, you could do that also. Na is +1, that makes a total of +2. Oxygen is -2 which makes a total of -6 for three of them. Now, what must C be to make zer?. It must be +4.
The charge of an ion is determined by the number of electrons it gains or loses to achieve a stable electron configuration. In the case of the carbonate ion (CO3^2-), we can determine its charge by understanding the valence electron configuration of each element it contains.
Carbon (C) belongs to Group 14 in the periodic table, which means it has four valence electrons. These electrons are located in the 2s^2 2p^2 orbitals. To achieve a stable electron configuration, carbon can either gain four electrons to complete its valence shell or lose four electrons to empty its valence shell. In the case of carbonate, carbon shares its four valence electrons with three oxygen atoms.
Oxygen (O) belongs to Group 16 in the periodic table, and it has six valence electrons. These electrons are located in the 2s^2 2p^4 orbitals. Each oxygen atom in the carbonate ion shares two of its valence electrons with carbon, forming double bonds. This leaves each oxygen with two unshared pairs of electrons, resulting in a formal charge of -2 for each oxygen atom.
By combining carbon and three oxygen atoms, we can determine the overall charge of the carbonate ion. Since each oxygen atom carries a charge of -2, the total charge contributed by the oxygen atoms is -6 (-2 * 3 = -6). To balance the overall charge of the ion, carbon must have a charge of +4 to cancel out the -6 charge from oxygen. Therefore, the carbonate ion has a charge of -2 to achieve electrical neutrality.
In summary, the charge of the carbonate ion (CO3^2-) is determined by the imbalance of electron sharing between carbon and oxygen. Carbon, which has a charge of +4, balances out the -6 charge contributed by three oxygen atoms, resulting in a -2 charge for the carbonate ion.