13. Lewis structure of NO₂^-, nitrite.

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1. Total number of valence shell electrons for all the atoms in NO₂^-. (Remember the charge)

	Wrong. Check the valence electrons of N and O. Also the charge.
	Wrong. Check the valence electrons of N and O. Also the charge..
	Correct. 18 electrones

2. Select the central atom:

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

3. How many electrons are used in the single bonds?:

	Wrong. Two single bonds require more than 4 electrons.
	Correct. Two N-O single bonds require 4 electrons

4. How many electrons are needed to complete the octeto of the terminal atoms?

	Wrong. Four electrons added to each O atom will not complete the octeto.
	Wrong. Five electrons added to each O atom will not complete the octeto.
	Correct. Six more electrons added to each O atom will complete the octeto. Total 12 electrons

5. How many electrons are required to complete the octeto in the central atom?

	Wrong. N already shares four electrons with the oxygen atoms. Two more electron will not complete the octeto
	Wrong. N already shares four electrons with the oxygen atoms. Three more electrons will not complete the octeto in N.
	Correct. N already shares four electrons with the oxygen atoms. Four more electrons will not complete the octeto in N; however there are only two electrons available. Try to place them

6. How is the geometry of NO₂^-.? Structures

	Wrong. N atom has a AEX2 environment.
	Wrong. N atom has a AEX2 environment. An angular 90° geometry is adopted by species with a AEX3 environment.
	Correct N has a AEX2 environment with two bond electron pairs and one unshared electron pair. AEX2

7. How is completed the octeto in N?

It does not complete the octeto.	Wrong. There is one way to complete the octeto.
Sharing one additional electron pair from one oxygen atom.	Correct The N atom forms a double bond with one oxygen ato. E Double bond

8. This representation shows two different N-O bonds for the nitrite ion. However all the experimental results support that both N-O bonds are identical. The Valence Bond theory explain this accepting that the structure of nitrite is a resonance between two resonance structures. There are alternative representations showing a N-O intermediate between single and double.

 

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