Question 1

Which of the following best explains why sodium (Na) forms a cation while chlorine (Cl) forms an anion in the formation of NaCl?
Correct answer: Sodium loses electrons to achieve a stable octet, while chlorine gains electrons to achieve a stable octet.

Accepted Answer

Sodium loses electrons to achieve a stable octet, while chlorine gains electrons to achieve a stable octet.

Question 2

Which of the following molecules is most likely to have an expanded octet in its Lewis structure?
Correct answer: SF6

Accepted Answer

SF6

Question 3

A molecule of carbon dioxide (CO2) is nonpolar, even though the C=O bonds are polar. Which concept best explains this observation?
Correct answer: The dipole moments of the two C=O bonds cancel each other due to the linear geometry.

Accepted Answer

The dipole moments of the two C=O bonds cancel each other due to the linear geometry.

Question 4

Which of the following statements about sigma (σ) and pi (π) bonds is correct?
Correct answer: A triple bond consists of one sigma and two pi bonds.

Accepted Answer

A triple bond consists of one sigma and two pi bonds.

Question 5

Which of the following best describes the role of formal charge in determining the best Lewis structure for a molecule?
Correct answer: The best Lewis structure minimizes formal charges and places negative charges on the most electronegative atoms.

Accepted Answer

The best Lewis structure minimizes formal charges and places negative charges on the most electronegative atoms.

Question 6

Which of the following elements is most likely to form a molecule with an incomplete octet?
Correct answer: Boron

Accepted Answer

Boron

Question 7

A student draws the Lewis structure for the nitrate ion (NO3−) and finds that the formal charge on nitrogen is +1, while each oxygen has a formal charge of -2 or 0. What error did the student most likely make?
Correct answer: They did not distribute the negative charge correctly among the oxygens.

Accepted Answer

They did not distribute the negative charge correctly among the oxygens.

Question 8

Which of the following best explains why metals are good conductors of electricity?
Correct answer: Metals have free-flowing valence electrons that can move throughout the lattice.

Accepted Answer

Metals have free-flowing valence electrons that can move throughout the lattice.

Question 9

Which of the following pairs of atoms would form the most polar covalent bond?
Correct answer: H–F

Accepted Answer

H–F

Question 10

A molecule has a central atom with three bonding pairs and one lone pair of electrons. Which of the following statements is true regarding its Lewis structure and geometry?
Correct answer: The molecule has a tetrahedral electron geometry and a trigonal pyramidal molecular geometry.

Accepted Answer

The molecule has a tetrahedral electron geometry and a trigonal pyramidal molecular geometry.

Question 11

Which of the following best describes the difference between ionic and covalent bonding?
Correct answer: Ionic bonding involves the transfer of electrons from metals to nonmetals, while covalent bonding involves the sharing of electrons between nonmetals.

Accepted Answer

Ionic bonding involves the transfer of electrons from metals to nonmetals, while covalent bonding involves the sharing of electrons between nonmetals.

Question 12

Which of the following statements about radicals is correct?
Correct answer: Radicals are molecules or ions with an unpaired electron, which is placed on the atom with the lowest formal charge.

Accepted Answer

Radicals are molecules or ions with an unpaired electron, which is placed on the atom with the lowest formal charge.

Question 13

Which of the following best explains why the bond length in N2 is shorter than in O2?
Correct answer: N2 has a triple bond (1 σ + 2 π), while O2 has a double bond (1 σ + 1 π), resulting in a shorter bond length for N2.

Accepted Answer

N2 has a triple bond (1 σ + 2 π), while O2 has a double bond (1 σ + 1 π), resulting in a shorter bond length for N2.

Question 14

Which of the following is the correct Lewis dot symbol for the chloride ion (Cl−)?
Correct answer: Cl with 8 dots and a negative charge

Accepted Answer

Cl with 8 dots and a negative charge

Question 15

A student is asked to draw the Lewis structure for $$SO4^2$$− (sulfate ion). Which of the following is a correct application of the octet rule and formal charge?
Correct answer: Sulfur can have an expanded octet, and the best structure minimizes formal charges, placing negative charges on the oxygens.

Accepted Answer

Sulfur can have an expanded octet, and the best structure minimizes formal charges, placing negative charges on the oxygens.

Question 16

Which of the following best describes the trend in electronegativity across the periodic table?
Correct answer: Electronegativity decreases down a group and increases across a period.

Accepted Answer

Electronegativity decreases down a group and increases across a period.

Question 17

Which of the following best explains why the O-H bond in water is polar?
Correct answer: There is a significant difference in electronegativity between oxygen and hydrogen, resulting in a dipole moment.

Accepted Answer

There is a significant difference in electronegativity between oxygen and hydrogen, resulting in a dipole moment.

Question 18

Which of the following is true regarding lone pairs in Lewis structures?
Correct answer: Lone pairs are nonbonding pairs of electrons on an atom.

Accepted Answer

Lone pairs are nonbonding pairs of electrons on an atom.

Question 19

A student is asked to compare the bond strengths and lengths of single, double, and triple bonds. Which of the following is correct?
Correct answer: Triple bonds are the shortest and strongest.

Accepted Answer

Triple bonds are the shortest and strongest.

Key Concepts in Chemical Bonding and Lewis Structures

Study Guide - Practice Questions

Study Guide - Flashcards