15. Lewis structure of CO₃^2-, carbonate anion.

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1. Compute the valence shell electrons for all the atoms in CO₃^2-. Remember the charge.

	Wrong. Check the valence electrons of C and O atoms and the charge.
	Correct. The total number of electrons is 24 electrons
	Wrong. Check the valence electrons of C and O atoms and the charge.

2. Select the central atom:

	Correct. Is the less electronegative atom. In this case C
	Wrong. The central atom is the less electronegative atom.

3. How many electrons are used in C-O single bonds?

	Wrong. Three C-O bonds require more electrons
	Correct. Three C-O bonds require un total de 6 electrons.

4. How many electrons are required to complete the octeto in the terminal atoms?.

	Wrong. Four additional electrons in each O atom do not complete the octeto.
	Wrong. Five additional electrons in each O atom do not complete the octeto.
	Correct. Six more electrons complete the octeto in each O atom. 18 electrons

5. The central atom needs two more electrons. But there are no more electrons available. What electron rearrangement can solve this problem?

Carbon remains as electron deficient with 6 electrons.	Wrong/b>. Carbon generally reaches the 8 electrons shell.
Shares one electron pair with oxygen	Correct. This electron transfer completes the octeto in C and creates a C=O double bond.

6.What is the geometry of this anion? Structures

	Wrong. This anion has a AX3 environment. Check the structures table.
	Wrong.This anion has a AX3 environment. Check the structures table.
	Correct For an structure of AX3 type, corresponds a una triangular planar structure..

7. Is this the final Lewis structure of CO₃^2- with one C=O double bond and two C-O single bonds?

Yes it is correct like that.	Wrong. This anion has the same C-O bond distances for all the oxygen atoms. One C=O double bond can be excluded.
The double bond is changing from one position to the others	Wrong. There is not such equilibrium
The Lewis structure is a resonance of all the three posible with the double bond located in each of the O atoms.	Correct. Read more

8. What orbitals uses the carbon atom?

	Wrong. The carbon atom has a AX3 environment and cannot use "p" orbitals.
	Correct. sp2 orbitals.	Correcto.
	Wrong. The carbon atom has a AX3 environment. "sp3" is not the correct answer.

We can also represent the orbitals participating in the pi bond that strengths the sigma bonds. This explanation requires the use of the Molecular Orbital model. It considers a four atoms-two electrons bond.