Draw the Lewis structure (including resonance structures) for methyl azide (CH₃N₃). For each resonance structure, assign formal charges to all atoms that have formal charge.

Verified step by step guidance

1. Identify the total number of valence electrons in the molecule. Carbon (C) has 4 valence electrons, each hydrogen (H) has 1, and each nitrogen (N) has 5. Since there are three hydrogens and three nitrogens, the total number of valence electrons is 4 (from C) + 3 (from H) + 15 (from N) = 22 electrons.
2. Draw the skeletal structure of methyl azide. Connect the carbon atom to the three hydrogen atoms forming CH3. Then, connect this CH3 group to one of the nitrogen atoms. Continue connecting the nitrogen atoms in a linear chain, N-N-N.
3. Distribute the remaining electrons to complete the octets of the nitrogen atoms. Start by placing lone pairs on the nitrogen atoms to fulfill the octet rule, remembering that each bond shared between atoms counts as two electrons towards each atom's octet.
4. Draw resonance structures by moving pi electrons between the nitrogen atoms. In azides, the negative charge can resonate between the terminal nitrogen atoms. Use arrows to show the movement of electrons and redraw the structure showing alternate double and single bonds between the nitrogen atoms.
5. Assign formal charges for each atom in every resonance structure. Remember, the formal charge is calculated using the formula: Formal Charge = (Valence electrons of the atom) - (Non-bonding electrons + 1/2 bonding electrons). Make sure to check each atom in every resonance structure.

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 use dots to represent valence electrons and lines to represent bonds. Understanding how to draw Lewis structures is essential for visualizing molecular geometry and predicting reactivity.

Resonance Structures

Resonance structures are different ways of drawing the same molecule that illustrate the delocalization of electrons. They are used when a single Lewis structure cannot adequately represent the electron distribution in a molecule. The actual structure is a hybrid of these resonance forms, which helps in understanding the stability and reactivity of the molecule.

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 bonds, and the number of lone electrons. It helps in determining the most stable Lewis structure by minimizing formal charges across the molecule. Assigning formal charges is crucial for evaluating resonance structures and understanding molecular stability.