Skip to main content
Pearson+ LogoPearson+ Logo
Ch.8 - Basic Concepts of Chemical Bonding
All textbooksBrown 15th EditionCh.8 - Basic Concepts of Chemical BondingProblem 96a
Chapter 8, Problem 96a

Mothballs are composed of naphthalene, C10H8, a molecule that consists of two six-membered rings of carbon fused along an edge, as shown in this incomplete Lewis structure:(a) Draw all of the resonance structures of naphthalene. How many are there?

Verified step by step guidance
1
Identify the structure of naphthalene, C_{10}H_{8}, which consists of two fused benzene rings.
Recall that benzene rings exhibit resonance, meaning that the electrons are delocalized over the carbon atoms.
For naphthalene, consider the delocalization of electrons across the entire structure, not just within individual rings.
Draw the first resonance structure by placing alternating single and double bonds around the rings, ensuring each carbon has four bonds.
Draw the second resonance structure by shifting the position of the double bonds, maintaining the delocalization of electrons across the rings.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
8m
Was this helpful?

Key Concepts

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

Resonance Structures

Resonance structures are different Lewis structures for the same molecule that depict the delocalization of electrons. In naphthalene, the pi electrons are shared between the two fused benzene rings, leading to multiple valid structures that contribute to the overall electron distribution. These structures help illustrate the stability and reactivity of the molecule.
Recommended video:
Guided course
01:42
Resonance Structures

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons. They provide a visual way to understand how atoms are connected and the arrangement of electrons. For naphthalene, drawing the Lewis structure involves placing the carbon and hydrogen atoms correctly and ensuring that the octet rule is satisfied for each carbon atom.
Recommended video:
Guided course
04:28
Lewis Dot Structures: Ions

Delocalization of Electrons

Delocalization of electrons refers to the phenomenon where electrons are not confined to a single bond or atom but are spread over several atoms. In naphthalene, the delocalized pi electrons across the carbon rings contribute to the molecule's stability and unique properties. This concept is crucial for understanding the resonance structures and the overall behavior of aromatic compounds.
Recommended video:
Guided course
03:56
Electron Geometry
Related Practice
Textbook Question

The hypochlorite ion, ClO-, is the active ingredient in bleach. The perchlorate ion, ClO4-, is a main component of rocket propellants. Draw Lewis structures for both ions. (b) What is the formal charge of Cl in the perchlorate ion, assuming the Cl—O bonds are all single bonds?

Textbook Question

The following three Lewis structures can be drawn for N2O:

(a) Using formal charges, which of these three resonance forms is likely to be the most important?

Textbook Question

The following three Lewis structures can be drawn for N2O:

(b) The N—N bond length in N2O is 1.12 Å, slightly longer than a typical N≡N bond; and the N—O bond length is 1.19 Å, slightly shorter than a typical N═O bond (see Table 8.4). Based on these data, which resonance structure best represents N2O?

Textbook Question

Mothballs are composed of naphthalene, C10H8, a molecule that consists of two six-membered rings of carbon fused along an edge, as shown in this incomplete Lewis structure:

(b) Do you expect the C—C bond lengths in the molecule to be similar to those of C—C single bonds, C ═C double bonds, or intermediate between C—C single and C ═C double bonds?

Textbook Question

Mothballs are composed of naphthalene, C10H8, a molecule that consists of two six-membered rings of carbon fused along an edge, as shown in this incomplete Lewis structure:

(c) Not all of the C—C bond lengths in naphthalene are equivalent. Based on your resonance structures, how many C—C bonds in the molecule do you expect to be shorter than the others?