Question 1

Which of the following statements best explains why rotation around a carbon-carbon double bond is restricted compared to a single bond?

Accepted Answer

Double bonds contain a pi bond, which results from the sideways overlap of p orbitals, preventing free rotation.

Question 2

Given the molecular formula $$\mathrm{C_2H_6O}$$, which of the following pairs are structural isomers?

Accepted Answer

Ethanol and dimethyl ether

Question 3

Which of the following molecules is expected to have the highest boiling point, and why?

A. $$\mathrm{CH_4$}

B$$. $$\mathrm{NH_3$}

C$$. $$\mathrm{CO_2$}

D$$. $$\mathrm{H_2$}$$

Accepted Answer

$$\mathrm{NH_3$}$$, because it can form hydrogen bonds.

Question 4

Which of the following best describes the difference between ionic and covalent bonding?

Accepted Answer

Ionic bonding involves the transfer of electrons, while covalent bonding involves the sharing of electrons.

Question 5

Which of the following molecules is polar, based on its Lewis structure and molecular geometry?

Accepted Answer

$$\mathrm{H_2O}$$

Question 6

What is the hybridization of the central atom in $$\mathrm{CH_4$}$$, and what is its molecular geometry?

Accepted Answer

sp$$^3$$ hybridization; tetrahedral geometry

Question 7

Which of the following best explains why sodium forms a $$+1$$ ion and chlorine forms a $$-1$$ ion in sodium chloride?

Accepted Answer

Sodium loses one electron to achieve a noble gas configuration, while chlorine gains one electron to achieve a noble gas configuration.

Question 8

Which of the following molecules can exhibit hydrogen bonding as an intermolecular force?

Accepted Answer

$$\mathrm{HF}$$

Question 9

Given the Lewis structure for $$\mathrm{NH_3$}$$, what is the electron pair geometry and the molecular shape?

Accepted Answer

Electron pair geometry: tetrahedral; Molecular shape: trigonal pyramidal

Question 10

Which of the following best explains why ionic compounds like $$\mathrm{NaCl}$$ have high melting points?

Accepted Answer

Strong electrostatic forces between oppositely charged ions require a large amount of energy to break.

Question 11

Which of the following statements about London dispersion forces is correct?

Accepted Answer

They are present in all molecules, but are the only intermolecular force in nonpolar molecules.

Question 12

Which of the following molecules has a linear molecular geometry according to VSEPR theory?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 13

Which of the following best describes why $$\mathrm{$$CCl_4$$} is $$nonpolar, even though it contains polar bonds?

Accepted Answer

The molecule is tetrahedral and the bond dipoles cancel out due to symmetry.

Question 14

Which of the following is the correct Lewis structure for $$\mathrm{O_2$}$$?

Accepted Answer

Each oxygen atom is connected by a double bond and each has two lone pairs.

Question 15

Which of the following compounds would you expect to have the lowest melting point?

Accepted Answer

$$\mathrm{CH_4$}$$

Question 16

Which of the following best explains why metals tend to form positive ions?

Accepted Answer

Metals have low ionization energies, so they lose electrons easily to achieve a stable electron configuration.

Question 17

Which of the following molecules has the greatest number of structural isomers?

Accepted Answer

$$\mathrm{C_4H_{10}}$$

Question 18

Which of the following best describes the structure of an ionic compound like $$\mathrm{NaCl}$$?

Accepted Answer

A repeating three-dimensional lattice of alternating positive and negative ions.

Question 19

Which of the following statements about the polarity of $$\mathrm{CO_2$} is $$correct?

Accepted Answer

$$\mathrm{CO_2$}$$ has polar bonds but is a nonpolar molecule due to its linear geometry.

Question 20

Which of the following best explains why $$\mathrm{H_2O}$$ has a higher boiling point than $$\mathrm{H_2S}$$?

Accepted Answer

$$\mathrm{H_2O}$$ forms stronger hydrogen bonds due to the higher electronegativity of oxygen.

Molecular Structure, Bonding, and Properties: A Study Guide

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