Question

Draw the principal resonance forms of the nitronium ion.

Short answer

The nitronium ion (NO₂⁺) has two principal resonance forms. In the first resonance structure, nitrogen is double bonded to one of the oxygen atoms and single bonded to the other. In the second resonance structure, the positions of the double and single bonds are reversed. Both structures show a positive charge on the central nitrogen atom. These resonance forms represent the resonance-stabilized distribution of electrons between the nitrogen and oxygen atoms.

Step-by-step solution

Determine Lewis Structure of Nitronium Ion

First, we need to draw the Lewis Structure of the nitronium ion (NO₂⁺). To do that, we will count the valence electrons of each atom and connect them with single bonds. Nitrogen has 5 valence electrons, and each oxygen atom has 6 valence electrons. Since the molecule has a positive charge, we will remove one electron. In total, there will be (5 + 6 + 6 - 1) = 16 valence electrons in the molecule.

Distribute the Remaining Electrons

Now, we need to distribute the remaining valence electrons as lone pairs around each atom to satisfy the octet rule (except for the central nitrogen atom in this case). Each oxygen atom is connected to the nitrogen atom with a single bond, which accounts for 4 electrons. We have 12 remaining electrons to distribute as lone pairs. Each oxygen atom will receive 3 lone pairs (6 electrons in total). This accounts for all 16 valence electrons.

Identify π Electrons and Bonding Atoms

Next, we need to identify the π electrons that can be involved in resonance and the atoms they are shared between. The π electrons are the lone pair electrons on oxygen atoms that are not being used for the single bond to nitrogen. The π electrons can be shared between the two oxygen atoms and the central nitrogen atom.

Draw Resonance Forms

To draw the resonance forms, we will show the alternate position of the π electrons being shared in the form of double bonds. The first resonance structure will have a double bond between nitrogen and one of the oxygen atoms, with the other oxygen atom having a single bond. The second resonance structure is formed by moving the double bond to the other oxygen atom, with the first oxygen atom now having a single bond. Make sure to include the positive charge on nitrogen atom. Here are the resonance structures for NO₂⁺ ion: ``` O O \\ // N⁺ N⁺ // \\ O O ``` The nitronium ion has two principal resonance forms, which represent the resonance-stabilized distribution of electrons between the nitrogen and oxygen atoms.

Key concepts

Lewis structure

The Lewis structure is a simple way to represent molecules and show how atoms are bonded together. It's a visual representation that helps in understanding the arrangement of valence electrons around atoms in a compound.
To construct a Lewis structure, follow these steps:

• Count the total number of valence electrons available in all the atoms of the molecule.
• Determine how atoms are arranged and connect them with single bonds.
• Distribute the remaining electrons as lone pairs to satisfy the bonding requirements of each atom, typically aiming to fulfill the octet rule.

In the case of the nitronium ion (NO₂⁺), a positive ion, you'll need to account for its charge by removing one electron from the total count. Understanding the Lewis structure is crucial as it serves as the foundation for determining resonance structures and predicting molecular geometry.

nitronium ion

The nitronium ion, represented as NO₂⁺, is a positively charged nitrogen-oxygen compound. It is a stable ion commonly encountered in the field of chemistry, particularly in nitrate salts and explosive compounds.
The nitronium ion is notable for its linear arrangement with the nitrogen atom at the center. It has a resonance-stabilized electronic structure, meaning that the actual distribution of electrons is a hybrid of multiple forms. This characteristic is critical because it affects the reactivity and stability of the ion in different chemical environments.
Understanding the nitronium ion's structure helps predict how it will interact with other chemical species, making it an important concept in organic and inorganic chemistry.

valence electrons

Valence electrons are the outermost electrons of an atom and are crucial for bonding. They play a key role in determining how atoms interact, bond, and form compounds.
For instance, in the nitronium ion (NO₂⁺), it's important to calculate the total number of valence electrons from nitrogen and oxygen atoms to correctly draw the Lewis structure. Each nitrogen atom has 5 valence electrons, while each oxygen atom has 6. Given the NO₂⁺ charge, you subtract one electron, leading to a total of 16 valence electrons.
By understanding the concept of valence electrons, you can analyze how elements bond and predict molecular structures. It's essential for grasping ideas like resonance and electron sharing.

octet rule

The octet rule is a chemical guideline that suggests atoms are most stable when they have eight electrons in their outer shell. This rule is a key factor in drawing Lewis structures and predicting molecular behavior.
Typically, atoms achieve an octet by forming bonds with other atoms, sharing, gaining, or losing electrons. In the nitronium ion, the nitrogen atom doesn't completely satisfy the octet rule itself. However, by forming bonds with oxygen atoms, it approaches this stable electronic configuration through resonance.
Although the octet rule has exceptions, such as molecules with odd numbers of electrons or transition metals, it's a helpful guideline for understanding molecular stability. Mastery of the octet rule enables better predictions of molecular structures and reactivity.