Question

Oxygen and nitrogen combine to form a variety of nitrogen oxides, including the following two unstable compounds that each have two nitrogen atoms per molecule: \(\mathrm{N}_{2} \mathrm{O}_{2}\) and \(\mathrm{N}_{2} \mathrm{O}_{3} .\) Draw Lewis structures for the molecules and show all resonance forms.

Short answer

Answer: The Lewis structures and resonance structures for N₂O₂ and N₂O₃ are: N₂O₂: 1. O: N = N : O 2. O : N - N : O N₂O₃: 1. O: O: O - N - N = O N = N - O | : : O - N - O O : O 2. O O : : N - N = O : O

Step-by-step solution

Determine the number of valence electrons for each element

Count the available valence electrons for each element in the compound. Oxygen has 6 valence electrons, and Nitrogen has 5 valence electrons. For N₂O₂, there are 2 nitrogen atoms and 2 oxygen atoms, so we have a total of \((2\times5) + (2\times6) = 22\) valence electrons. For N₂O₃, there are 2 nitrogen atoms and 3 oxygen atoms, giving us a total of \((2\times5) + (3\times6) = 28\) valence electrons.

Draw the skeletal structures for N₂O₂ and N₂O₃

For N₂O₂, start by connecting the two nitrogen atoms and then attach oxygen atoms to each nitrogen atom like this: ``` O-N-N-O ``` Now for N₂O₃, start by connecting the two nitrogen atoms and then attach two oxygen atoms to one nitrogen atom and one oxygen atom to the other one like this: ``` O-N-N-O | O ```

Complete the Lewis structures by adding valence electrons

For N₂O₂, complete the structure by adding lone pairs of electrons to fill the octets of the nitrogen and oxygen atoms: ``` O : N = N : O ``` For N₂O₃, complete the structure by adding lone pairs of electrons to fill the octets of the nitrogen and oxygen atoms: ``` O O : : N = N - O ```

Identify resonance structures if any

For N₂O₂, there is one more resonance structure where the double bond between the nitrogen atoms can be shifted, which gives: ``` O : N - N : O ``` For N₂O₃, there are two more resonance structures where the double bond between the nitrogen and oxygen can be shifted. They are: ``` O O O - N - N = O : : | : N - N = O O - N - O : : O O ``` To summarize, the Lewis structures and resonance structures of N₂O₂ and N₂O₃ are as follows: - N₂O₂: 1. O: N = N : O 2. O : N - N : O - N₂O₃: 1. O: O: O - N - N = O N = N - O | : : O - N - O O : O 2. O O : : N - N = O : O

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom and play a crucial role in chemical bonding and molecule stability. These electrons are responsible for forming chemical bonds between atoms. To draw Lewis structures, which are diagrams that show the bonding between atoms and the lone pairs of electrons that may exist in the molecule, you need to first count the available valence electrons for the involved atoms.

For compounds like nitrogen oxides, such as \(N_2O_2\) and \(N_2O_3\), identifying the number of valence electrons is vital. Nitrogen typically has 5 valence electrons, and oxygen has 6. When calculating total valence electrons:

• For \(N_2O_2\), use the formula \((2\times5) + (2\times6) = 22\) valence electrons.
• For \(N_2O_3\), it's \((2\times5) + (3\times6) = 28\) valence electrons.

This information provides the basis for constructing accurate Lewis structures before considering bonding and placement in the molecules.

Resonance Structures

Resonance structures are multiple Lewis structures that can represent the same molecule. These structures help to describe the delocalization of electrons within certain molecules where the electrons can be placed in more than one position. In resonance, no single structure is correct on its own, and the actual molecule is typically a hybrid of all possible structures.

For the nitrogen oxide molecules like \(N_2O_2\), resonance structures are identified by shifting the position of electrons or bonds. For instance, shifting the double bonds between nitrogen atoms creates different forms, showcasing the molecule's electron delocalization potential. In \(N_2O_2\), moving the double bond from one nitrogen atom to another gives you another resonance form. Similarly, in \(N_2O_3\), moving double bonds between nitrogen and oxygen atoms gives rise to new resonance forms.

• Each resonance structure must be valid with proper valence electron counts.
• Structures should maintain overall neutrality and fulfill the octet rule wherever possible.

Through resonance, these compounds exhibit stability and flexibility in their electron configurations.

Nitrogen Oxides

Nitrogen oxides are a group of compounds containing nitrogen and oxygen, where both atoms can form several types of bonds thanks to their valence electrons. These oxides are often unstable due to the multiple possible bonding patterns, which can be represented by the resonance structures in their Lewis diagrams.

In \(N_2O_2\) and \(N_2O_3\), nitrogen atoms connect with multiple oxygen atoms to form various oxides, which are significant in industrial applications and environmental chemistry.

• \(N_2O_2\) and \(N_2O_3\) often exist as temporary intermediates or reactive species in chemical reactions.
• These compounds can readily participate in chemical reactions due to their often unstable bonds, which can shift easily.

This shifting is illustrated by their resonance structures, which depict potential configurations of electrons and bonds. Understanding these structures and the role of valence electrons and resonance assists in predicting the behavior of nitrogen oxides in various chemical contexts.