Chapter 4, Problem 4.1PP

Summary Introduction

To determine:

The difference between a Lewis structure and a condensed structure in terms of atoms and bonds is shown in the structure.

Introduction:

The molecules of organic compounds are represented by four different ways namely, Lewis structure, skeletal formula, condensed structural formula, and ball-and-stick model.

Lewis structures show all atoms, bonds, and lone pairs of atoms in the molecule. It helps in predicting the molecular geometry and shows the connectivity of atoms in a molecule whereas, condensed structural formula is simpler as it does not show any bonds or lone pairs of atoms and shows no connectivity of atoms in a molecule.

Explanation of Solution

The example of butanol molecule is to be assumed.

The Lewis structure of butanol molecule is represented as,

Fig.1

The number of bonds of each atom depends on the valence electrons of atoms in a molecule.

Figure 1 shows the Lewis structure in which carbon has $4$ valence electrons so that it forms four bonds with other atoms, and hydrogen has one valence electron so that it forms one bond with another atom. The number of valence electrons of oxygen is six. In Figure 1, two electrons of oxygen form bonds with two atoms and the remaining four electrons are present as lone pairs.

Condensed structure shows the shorter way to draw a molecule and is more simplified than the Lewis structure. It shows all atoms except the vertical bonds and most or all the horizontal bonds.

The condensed structure of butanol molecule is represented as,

${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$

In this formula, first carbon atom has three hydrogen atoms bonded to it; the second, third, and fourth carbon has two hydrogen atoms. The two lone pair on oxygen atoms are not shown as in condensed structure of atoms. Lone pair is not represented in the chemical symbol of atom.

Conclusion

Lewis structure is the most expanded structure as it shows all atoms, bonds, and lone pairs of atoms in a molecule whereas, condensed structure is the least expanded as it does not show all the bonds and lone pairs of atoms. Condensed structure is simpler than the Lewis structure.