$$FC = \text{valence electrons} - [\text{nonbonding electrons} + \frac{1}{2} \text{bonding electrons}]$$

Question 1

Which of the following statements best describes electronegativity?

Accepted Answer

It is the ability of an atom to attract bonding electrons to itself.

Question 2

Arrange the following elements in order of decreasing electronegativity: P, Na, N, Al.

Accepted Answer

N \u003e P \u003e Al \u003e Na

Question 3

A bond between two atoms has an electronegativity difference ($$\Delta EN) of 2.5. $$What type of bond is most likely present?

Accepted Answer

Ionic bond

Question 4

Which molecule would you expect to have a dipole moment closest to zero?

Accepted Answer

Cl$$_2$$

Question 5

The percent ionic character of a bond is defined as:

Accepted Answer

The percentage of a bond's measured dipole moment compared to what it would be if the electrons were completely transferred.

Question 6

Which of the following molecules is most likely to be classified as a free radical?

Accepted Answer

ClO

Question 7

Which molecule could have an expanded octet?

Accepted Answer

H$$_3PO$_4$$

Question 8

Which of the following is the correct formula for calculating the formal charge ($$FC) of an $$atom in a Lewis structure?

Accepted Answer

$$FC = 	ext{valence electrons} - [	ext{nonbonding electrons} + \frac{1}{2} 	ext{bonding electrons}]$$

Question 9

Which of the following is NOT a rule for evaluating resonance structures?

Accepted Answer

Positive formal charge should always be placed on the most electronegative atom.

Question 10

Which of the following molecules exhibits resonance?

Accepted Answer

O$$_3$$

Question 11

Which statement about bond energy is correct?

Accepted Answer

Bond energy increases as bond order increases.

Question 12

Given the following bonds, which has the shortest bond length?

Accepted Answer

C≡N (triple bond)

Question 13

Which of the following trends is correct regarding bond length in the periodic table?

Accepted Answer

Bond length increases down a group and decreases across a period.

Question 14

A molecule has a measured dipole moment of 1.82 D and an electronegativity difference of 1.9. What is the percent ionic character likely to be?

Accepted Answer

Less than 50%

Question 15

Which of the following is an exception to the octet rule?

Accepted Answer

NO (odd number of electrons)

Question 16

Which of the following best explains why resonance structures stabilize a molecule?

Accepted Answer

Delocalization of charge reduces electron repulsion and distributes energy more evenly.

Question 17

Which of the following bonds would have the highest bond energy?

Accepted Answer

N≡N (triple bond)

Question 18

Which of the following statements about dipole moments is correct?

Accepted Answer

Dipole moment is directly proportional to the size of the partial charges and the distance between them.

Question 19

Which of the following molecules is most likely to have a bond with greater than 50% ionic character?

Accepted Answer

LiF

Question 20

Which step is NOT part of the process for writing Lewis structures?

Accepted Answer

Assigning formal charges to maximize the number of atoms with positive charges.

Chemical Bonding I: The Lewis Model – Electronegativity, Bond Polarity, Resonance, Formal Charge, and Bond Energies

Study Guide - Practice Questions