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Chapter 1: Structure and Bonding

Every problem in the chapter beside the book’s answer, a chapter at a time as you scroll.

Chapter 1: Structure and Bonding

17 problems · 27 figures

1-1 §1.3 source ↗

What is the ground-state electron configuration of each of the following elements:
(a)
Oxygen
(b)
Nitrogen
(c)
Sulfur

Answer (3 parts)

(a)
1s2 2s2 2p4
(b)
1s2 2s2 2p3
(c)
1s2 2s2 2p6 3s2 3p4

1-2 §1.3 source ↗

How many electrons does each of the following biological trace elements have in its outermost electron shell?
(a)
Magnesium
(b)
Cobalt
(c)
Selenium

Answer (3 parts)

(a)
2
(b)
2
(c)
6

1-3 §1.4 source ↗

Draw a molecule of chloroform, CHCl3, using solid, wedged, and dashed lines to show its tetrahedral geometry.

Answer

1-4 §1.4 source ↗

Convert the following representation of ethane, C2H6, into a conventional drawing that uses solid, wedged, and dashed lines to indicate tetrahedral geometry around each carbon (black = C, gray = H).

Answer

1-5 §1.4 source ↗

What are likely formulas for the following substances?
(a)
CCl?
(b)
AlH?
(c)
CH?Cl2
(d)
SiF
(e)
CH3NH?

Answer (5 parts)

(a)
CCl4
(b)
AlH3
(c)
CH2Cl2
(d)
SiF4
(e)
CH3NH2

1-6 §1.4 source ↗

Write line-bond structures for the following substances, showing all nonbonding electrons:
(a)
CHCl3, chloroform
(b)
H2S, hydrogen sulfide
(c)
CH3NH2, methylamine
(d)
CH3Li, methyllithium

Answer (4 parts)

(a)
(b)
(c)
(d)

1-7 §1.4 source ↗

Why can’t an organic molecule have the formula C2H7?

Answer

C2H7 has too many hydrogens for a compound with two carbons.

1-8 §1.7 source ↗

Draw a line-bond structure for propane, CH3CH2CH3. Predict the value of each bond angle, and indicate the overall shape of the molecule.

Answer

1-9 §1.7 source ↗

Convert the following molecular model of hexane, a component of gasoline, into a line-bond structure (black = C, gray = H).

Answer

1-10 §1.8 source ↗

Draw a line-bond structure for propene, CH3CH = CH2. Indicate the hybridization of the orbitals on each carbon, and predict the value of each bond angle.

Answer

The CH3 carbon is sp3; the double-bond carbons are sp2; the C = C−C and C = C−H bond angles are approximately 120°; other bond angles are near 109°.

1-11 §1.8 source ↗

Draw a line-bond structure for 1,3-butadiene, H2C = CH–CH = CH2. Indicate the hybridization of the orbitals on each carbon, and predict the value of each bond angle.

Answer

All carbons are sp2, and all bond angles are near 120°.

1-12 §1.8 source ↗

A molecular model of aspirin (acetylsalicylic acid) is shown. Identify the hybridization of the orbitals on each carbon atom in aspirin, and tell which atoms have lone pairs of electrons (black = C, red = O, gray = H).

Answer

All carbons except CH3 are sp2.

1-13 §1.9 source ↗

Draw a line-bond structure for propyne, CH3C ≡ CH. Indicate the hybridization of the orbitals on each carbon, and predict a value for each bond angle.

Answer

The CH3 carbon is sp3; the triple-bond carbons are sp; the C ≡ C−C and H−C ≡ C bond angles are approximately 180°.

1-14 §1.10 source ↗

Identify all nonbonding lone pairs of electrons in the following molecules, and tell what geometry you expect for each of the indicated atoms.
(a)
The oxygen atom in dimethyl ether, CH3–O–CH3
(b)
The nitrogen atom in trimethylamine,
(c)
The phosphorus atom in phosphine, PH3
(d)
The sulfur atom in the amino acid methionine,

Answer (4 parts)

(a)
O has 2 lone pairs and is sp3-hybridized.
(b)
N has 1 lone pair and is sp3-hybridized.
(c)
P has 1 lone pair and is sp3-hybridized.
(d)
S has 2 lone pairs and is sp3-hybridized.

1-15 §1.12 source ↗

How many hydrogens are bonded to each carbon in the following compounds, and what is the molecular formula of each substance?
(a)
(b)

Answer (2 parts)

(a)
(b)

1-16 §1.12 source ↗

Propose skeletal structures for compounds that satisfy the following molecular formulas: There is more than one possibility in each case.
(a)
C5H12
(b)
C2H7N
(c)
C3H6O
(d)
C4H9Cl

Answer (4 parts)

(a)
There are numerous possibilities, such as:
(b)
There are numerous possibilities, such as:
(c)
There are numerous possibilities, such as:
(d)
There are numerous possibilities, such as:

1-17 §1.12 source ↗

The following molecular model is a representation of para-aminobenzoic acid (PABA), the active ingredient in many sunscreens. Indicate the positions of the multiple bonds, and draw a skeletal structure (black = C, red = O, blue = N, gray = H).

Answer

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Problems and answers are adapted from Organic Chemistry: A Tenth Edition by John McMurry, OpenStax, and are used under the CC BY-NC-SA 4.0 licence. Access for free at https://openstax.org/books/organic-chemistry/pages/1-why-this-chapter. Illustrations: Copyright Rice University, OpenStax, under CC BY-NC-SA 4.0 license. This adaptation is released under the same licence, is non-commercial, and is neither affiliated with nor endorsed by OpenStax or Rice University.