Question

Resonance structures of a molecule does not have (a) identical arrangement of atoms (b) nearly the same energy content (c) same number of paired electrons (d) identical bonding

Short answer

(d) identical bonding

Step-by-step solution

Understand Resonance Structures

Resonance structures are different ways of drawing the same molecule, which help to represent delocalized electrons within a molecule. While these structures involve different possible arrangements of double and single bonds, the atoms remain in the same position across all resonance structures.

Analyze the Answer Choices

Examine each option to determine if it fits the characteristics of resonance structures. - (a) Identical arrangement of atoms: Resonance structures have the same arrangement of atoms, only the electron distribution changes. - (b) Nearly the same energy content: Resonance structures represent the same molecule and are typically of similar energy. - (c) Same number of paired electrons: They have the same number of electrons overall. - (d) Identical bonding: Resonance involves different bonding arrangements being represented.

Determine the Incorrect Characteristic

Since resonance structures involve different bonding arrangements while maintaining the same atomic positions, option (d) 'identical bonding' is incorrect. Resonance structures show different possible double/single bond positions, so they do not have identical bonding.

Key concepts

Molecular Structure

When discussing resonance structures, it's important to first understand the molecular structure of a compound. The molecular structure refers to the 3D arrangement of atoms within a molecule. This is the skeleton around which everything else is built.

• **Atoms' Positions:** In resonance structures, the positions of atoms remain fixed. Imagine a house where the walls never move, no matter how you redecorate.
• **Importance:** The fixed atomic positions ensure that all resonance structures refer to the same basic molecule.

Even though the electrons may move around, the molecular structure remains constant. This consistency helps maintain the integrity of the molecule while allowing for other changes in electron distribution.

Electron Distribution

Electron distribution is a fundamental aspect of understanding resonance structures. It refers to how electrons are spread across different atoms and bonds in a molecule.

• **Delocalization of Electrons:** In resonance structures, electrons are represented as delocalized, meaning they aren't tied down to a single bond or atom.
• **Electron Cloud:** Picture it as a cloud that can shift and change shape while covering the same area. This behavior is what gives resonance structures their flexibility with different bonding patterns.
• **Stability:** Delocalization can contribute to extra stability for the molecule, as the electron cloud can distribute energy more evenly across the structure.

These shifts in electron distribution lead us to recognize that certain resonance structures are more favorable energetically than others, although they represent the same molecule.

Bonding Arrangements

Bonding arrangements are another key concept when exploring resonance structures. This involves the type and placement of chemical bonds between atoms in a molecule.

• **Variability in Bonds:** Unlike the atomic positions and number of electrons, bonding arrangements can vary between resonance structures. This means single, double, or even triple bonds can switch places.
• **Visualization:** Think of it as rearranging furniture in a room; the walls remain the same, but the layout changes. This allows different possible structures that represent the same molecule.
• **Impact on Properties:** These different arrangements play a role in how the molecule interacts with other substances, and can affect its properties like reactivity and polarity.

While these changes provide flexibility, they do not change the inherent nature of the molecule as described by its molecular structure.