Draw the Lewis structure for nitric acid, ensuring the hydrogen atom is attached to one of the oxygen atoms. Include all three resonance structures by alternating the double bond among the three oxygen atoms. Use formal charge to determine which of the resonance structures is most important to the structure of nitric acid.

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Identify the total number of valence electrons in nitric acid (HNO₃). Hydrogen has 1, nitrogen has 5, and each oxygen has 6, giving a total of 24 valence electrons.

Draw the skeletal structure of HNO₃ with nitrogen as the central atom, bonded to one hydrogen and three oxygen atoms. Initially, connect each atom with single bonds.

Distribute the remaining valence electrons to satisfy the octet rule for each atom, starting with the outer atoms (oxygen) and then the central atom (nitrogen).

Create double bonds between nitrogen and one of the oxygen atoms to satisfy the octet rule for nitrogen. Repeat this process to form the three resonance structures by alternating the double bond among the three oxygen atoms.

Calculate the formal charge for each atom in all three resonance structures. The most stable resonance structure will have the formal charges closest to zero, with negative charges on the more electronegative atoms (oxygen).

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

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. In the case of nitric acid, the Lewis structure will show how the hydrogen atom is bonded to one of the oxygen atoms, and how the remaining oxygen atoms are connected through double and single bonds.

Resonance Structures

Resonance structures are different ways of drawing the same molecule that illustrate the delocalization of electrons. In nitric acid, resonance structures show how the double bond can shift among the three oxygen atoms. This concept is crucial for understanding the actual electron distribution in the molecule, which is a hybrid of all possible resonance forms.

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 determine the most stable resonance structure by indicating which structure has the lowest formal charges on the atoms. In nitric acid, analyzing formal charges allows us to identify which resonance structure contributes most to the overall structure of the molecule.

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Formal Charge

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