Lewis structure of carbonate ion is drawn in this tutorial step by step. Total valence electrons concept is used to draw the lewis structure of CO32-. After finishing the lewis structure of CO32-, there should be a -2 charge and it should be stabile structure. You will learn about these facts in this tutorial.
Carbonate ion has a -2 charge. Metal carbonate compounds are common in the world. As an CaCO3 can be given.
There are three σ bonds and π bond around carbon atom in the Lewis structure of CO32- ion.
Following steps are required to draw the CO32- lewis structure and they are explained in detail in this tutorial.
Drawing correct lewis structure is important to draw resonance structures of CO32- correctly.
Carbon is located at group 4 in the periodic table. So, carbon has four electrons in its valence shell.Oxygen is located at 6th group. It has six electrons in valence shell.
There are three oxygen atoms in CO32- ion, Therefore
There are -2 charge on CO32- ion. Therefore there are two more electrons which contribute to the valence electrons.
Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells
Total electron pairs are determined by dividing the number total valence electrons by two. For, CO32- ion, Total pairs of electrons are 12.
To be the center atom, ability of having higher valance is important. Carbon has the more chance to be the center atom (See the figure) because carbon can show valance of 4. Oxygen's highest valence is 2. So, now we can build a sketch of CO32- ion.
After, marking electron pairs on atoms, we should mark charges of each atom. Marking of charges are significant because it is used to determine the best lewis structure of the ion. After marking charges, you will see, each oxygen atom will get a -1 charge and carbon atom get a +1 charge.
In new structure, charges of atoms are reduced than previous structure. Now there are no charge on on one oxygen atom and the carbon atom. Also, only two oxygen atoms have -1 negative charges. Now you understand this structure of CO32- is more stable than previous structure. So, this structure has more chance to be the lewis structure of CO32- ion.
In carbonate ion, there is two oxygen atoms which has -1 charge on each of them. One of these oxygen atom take a proton (H+ ion) and form a -OH group.