Question

The structures of ${O_3}$ and $N_3^ - $ are:
A) linear and bent, respectively
B) both linear
C) both bent
D) bent and linear, respectively

Answer 1

Hint: Recall the lewis representation of molecules. The lewis dot structure gives a picture of the bonding in molecules and ions in terms of the shared bonding pairs and follows the octet rule. Draw the lewis dot structures of ${O_3}$ and $N_3^ - $ to get the answer.

Complete step by step answer:
Let us proceed in steps to draw the lewis structures of the molecule ${O_3}$:
Step 1. Count the number of valence electrons of oxygen atoms. The outer valence shell electronic configuration of O is $2{s^2}2{p^4}$. Therefore, valence electrons of three oxygen molecules are 6 + 6 + 6 = 18.
Step 2. Draw the skeletal structure of ${O_3}$ as: O O O
Step 3. Draw a single bond (one shared electron pair) between the two oxygen atoms completing the octet on each oxygen atom. However, we have to draw a double bond between two oxygen atoms. The remaining electrons after completing the octet on each atom constitute lone pairs.
We get the structure as:

Thus, we get the structure of ${O_3}$ as bent.

Now, lewis structures of the molecule $N_3^ - $:
Step 1. Count the number of valence electrons of nitrogen atoms. The outer valence shell electronic configuration of N is $2{s^2}2{p^3}$. Therefore, valence electrons of three nitrogen atoms are 5+5+5 = 15.
Step 2. Draw the skeletal structure of $N_3^ - $ as: N N N
Step 3. Draw a single bond (one shared electron pair) between the two nitrogen atoms completing the octet on each nitrogen atom. However, we have to draw a double bond between two nitrogen atoms to complete the octets. The remaining electrons after completing the octet on each atom constitute lone pairs. There is a negative charge too on the molecule which means we need to add one extra electron in the structure. So, there are a total of 16 electrons in the $N_3^ - $ molecule. We can show negative charge on the whole sphere in the structure of molecules.
We get the structure as:

Thus, the structure of $N_3^ - $ molecule is linear in shape.
Hence, the structures of ${O_3}$ and $N_3^ - $ are bent and linear respectively.
So, the correct answer is “Option D”.

Note: ${O_3}$ is known as ozone and $N_3^ - $ is known as azide ion. Ozone molecules show two resonance structures. Azide ion can also show various resonance structures, but an important one is as shown below: