Sodium azide is a shock-sensitive compound that releases N2 upon physical impact. The compound is used in automobile airbags. The azide ion is N3-. (a) Draw the Lewis structure of the azide ion that minimizes formal charge (it does not form a triangle). Is it linear or bent?

Verified step by step guidance

1. insert step 1> Start by determining the total number of valence electrons for the azide ion, \( \text{N}_3^- \). Each nitrogen atom has 5 valence electrons, and the extra negative charge adds 1 more electron, giving a total of 16 valence electrons.
2. insert step 2> Arrange the three nitrogen atoms in a linear sequence, as the problem states it does not form a triangle.
3. insert step 3> Distribute the electrons to form bonds between the nitrogen atoms. Start by placing a single bond between each pair of nitrogen atoms, using 4 electrons (2 for each bond).
4. insert step 4> Distribute the remaining 12 electrons to satisfy the octet rule for each nitrogen atom. Place lone pairs on the outer nitrogen atoms first, then adjust the bonding to minimize formal charges.
5. insert step 5> Calculate the formal charge for each nitrogen atom to ensure the structure minimizes formal charges. The azide ion should have a linear structure with formal charges minimized.

Key Concepts

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons that may exist. They help visualize the arrangement of electrons and the connectivity of atoms, allowing for the determination of molecular geometry and formal charges. In the case of the azide ion (N3-), drawing the correct Lewis structure is essential to understand its stability and reactivity.

Formal Charge

Formal charge is a theoretical charge assigned to an atom in a molecule, calculated based on the number of valence electrons, the number of non-bonding electrons, and half the number of bonding electrons. It helps in assessing the most stable Lewis structure by minimizing the formal charges across the molecule. For the azide ion, minimizing formal charge is crucial to determine the most favorable electron distribution.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule, which is influenced by the repulsion between electron pairs according to VSEPR (Valence Shell Electron Pair Repulsion) theory. The azide ion's geometry can be determined from its Lewis structure, indicating whether it is linear or bent. In the case of N3-, the arrangement is linear due to the presence of triple bonds between nitrogen atoms.