Question

Pick out the wrong statement about resonance. (1) Resonance structures should have cqual cnergy. (2) In resonance structures, the constitucnt atoms must be in the same position. (3) In resonance structures, all the clectrons may be paired or may be arranged in pairs or unpaired clectrons. (4) Resonance structures should differ only in the location of clectrons around the constituent atoms.

Short answer

Statement 3 is incorrect.

Step-by-step solution

Understand Resonance Structures

Resonance structures represent different possible configurations for a molecule where the arrangement of electrons changes, but the placement of atoms stays the same. Resonance stabilizes the molecule.

Evaluate Each Statement

Evaluate the given statements to determine if they accurately describe characteristics of resonance structures.

Check Energy Equality

Statement 1: Resonance structures should have equal energy. This statement is true; resonance forms are only significant when they have similar energy levels.

Check Atom Positions

Statement 2: In resonance structures, the constituent atoms must be in the same position. This is correct; only the electrons can move, not the positions of the atoms.

Check Electron Pairing

Statement 3: In resonance structures, all the electrons may be paired or may be arranged in pairs or unpaired electrons. This is incorrect; resonance structures typically involve paired electrons.

Check Electron Locations

Statement 4: Resonance structures should differ only in the location of electrons around the constituent atoms. This statement is valid; different resonance forms only vary by the positions of electrons.

Identify the Incorrect Statement

Based on the evaluation, Statement 3 is the incorrect statement about resonance.

Key concepts

chemical bonding

Chemical bonding is the process where atoms combine to form molecules and compounds. This occurs because atoms seek to achieve a more stable electron configuration. There are various types of chemical bonds, including ionic, covalent, and metallic bonds.
In covalent bonding, atoms share electrons to achieve stability. Due to this sharing, the shape and stability of molecules are determined. This is where resonance structures become significant. Resonance structures are particularly important for understanding how electrons can be arranged in a molecule.
Resonance helps to explain the bonding in molecules that can’t be adequately described by a single structure. It distributes the electron density over multiple structures, reducing the potential energy of the molecule and thus stabilizing it.

• Helps achieve stable configurations
• Describes electron sharing in bonds
• Important for understanding complex molecules like benzene

electron configuration

Electron configuration refers to the arrangement of electrons in an atom's electron shells and subshells. The configuration helps determine the chemical properties and reactivity of the atom. For example, noble gases have a full valence shell, making them generally unreactive.
In the context of resonance structures, electron configuration helps explain why certain atoms or molecules act in certain ways. Different resonance structures show different potential configurations of electrons in a molecule. These configurations contribute to the overall stability of the molecule.
Each resonance structure is a different way to arrange the electrons without changing the positions of the atoms, providing multiple ways to represent the same molecule. Correct electron configuration is essential for accurately writing and predicting these structures.

• Determines atomic properties
• Explains electron arrangements in resonance
• Important for predicting molecular behavior

molecular stability

Molecular stability refers to how resistant a molecule is to changing its structure or breaking apart. Stability is influenced by factors like electron configurations, the type of bonding, and resonance structures.
Resonance structures contribute greatly to molecular stability. When electrons are delocalized over multiple resonance structures, the molecule's potential energy is lowered. This delocalization stabilizes the molecule because it distributes electron density evenly, preventing any one part of the molecule from becoming too electron-rich or electron-poor.
Resonance-stabilized molecules, such as benzene, are more stable than their single-structure counterparts. The stabilization makes the molecules less reactive in certain situations.

• Increased by resonance
• Delocalization helps lower energy
• Makes molecules less reactive

energy levels

Energy levels in atoms and molecules refer to the fixed energies that electrons can have. Electrons occupy orbitals, which have specific energy levels. Resonance structures affect these energy levels by providing multiple ways to distribute electrons.
When a molecule has resonance structures, the actual energy level of the molecule is an average of the energies of these structures. This averaging often results in lower overall energy for the molecule, contributing to greater stability.
In resonance structures, while electrons can be moved between orbitals of different energies, the positions of the atoms stay the same, ensuring that the arrangement remains consistent while the distribution of energy is optimized.

• Defines fixed electron energies
• Resonance averages energy
• Contributes to molecular stability