To draw the Lewis structure for CO3^2- (carbonate ion), follow these steps:
1. **Count the total number of valence electrons**: Carbon (C) has 4 valence electrons, and each oxygen (O) has 6 valence electrons. Since there are 3 oxygen atoms, the total number of valence electrons is 4 + (3 × 6) = 22. However, since the ion has a 2- charge, we add 2 more electrons, making it 24 valence electrons in total.
2. **Place the least electronegative atom in the center**: Carbon is less electronegative than oxygen, so it will be the central atom.
3. **Connect the atoms with single bonds**: Draw single bonds between the carbon atom and each of the three oxygen atoms. This uses 6 electrons (3 bonds × 2 electrons).
4. **Distribute the remaining electrons**: After forming the single bonds, you have 18 electrons left. Place these electrons around the oxygen atoms to satisfy the octet rule. Each oxygen atom should have 8 electrons around it, including the electrons in the bonds.
5. **Check for octet completion**: After distributing the electrons, you will notice that the carbon atom has only 6 electrons around it, which means it does not satisfy the octet rule. To fix this, one of the oxygen atoms will form a double bond with the carbon atom. This will use 2 more electrons, leaving you with 16 electrons.
6. **Finalize the structure**: After forming the double bond, the carbon atom now has 8 electrons around it, satisfying the octet rule. The final Lewis structure will have one double bond between carbon and one oxygen atom, and two single bonds between carbon and the other two oxygen atoms.
**Answering the questions:**
a. **Number of lone pairs**: Each oxygen atom has 2 lone pairs, except for the oxygen atom that forms the double bond with carbon, which has 1 lone pair.
b. **Number of single bonds**: There are 2 single bonds between carbon and two oxygen atoms.
c. **Number of double bonds**: There is 1 double bond between carbon and one oxygen atom.
d. **Does carbon meet the octet rule?**: Yes, after forming the double bond, carbon has 8 electrons around it, satisfying the octet rule.
This structure ensures that all atoms have the appropriate number of electrons and that the carbonate ion is correctly represented.