Question 1

Which of the following statements best describes why atoms form chemical bonds?

Accepted Answer

To lower the potential energy between charged particles and achieve stable electron configurations

Question 2

How many valence electrons (dots) are present in the Lewis dot symbol for phosphorus?

Accepted Answer

5

Question 3

Which of the following pairs of elements will form an ionic bond?

Accepted Answer

Na and Cl

Question 4

What is the general trend for electronegativity across the periodic table?

Accepted Answer

Electronegativity increases from left to right across a period and decreases from top to bottom in a group

Question 5

Given the following electronegativity values: $$x_{Na} = 0.93$$, $$x_{Cl} = 3.16$$, what is the ionic character (IC) of NaCl?

Accepted Answer

$$IC = |0.93 - 3.16| = 2.23$$

Question 6

Which of the following molecules has a pure covalent bond?

Accepted Answer

Cl$$_2$$

Question 7

What is the formula for calculating the dipole moment ($$\mu) of a $$bond?

Accepted Answer

$$\mu = q 	imes r$$

Question 8

In the Lewis structure for SrBr$$_2$$, how many electrons are on each Br atom?

Accepted Answer

8 (from the octet rule, but including the original 7 valence electrons plus one gained, total is 8)

Question 9

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

Accepted Answer

BF$$_3$$

Question 10

Which atom is most likely to have an incomplete octet in a stable molecule?

Accepted Answer

Boron

Question 11

Which of the following molecules must use an expanded octet in its Lewis structure?

Accepted Answer

SF$$_6$$

Question 12

Resonance structures differ in:

Accepted Answer

The position of the electrons

Question 13

What is the formal charge on the carbon atom in carbon monoxide (CO)?

Accepted Answer

-1

Question 14

Which of the following substances has the longest carbon-oxygen bond?

Accepted Answer

CO$$_3$$^{2-}$$

Question 15

When drawing the Lewis structure for CH$$_2O$$, what is the total number of valence electrons to distribute?

Accepted Answer

12

Question 16

Which of the following is true about formal charge assignment in Lewis structures?

Accepted Answer

Negative formal charges should be placed on more electronegative atoms

Question 17

Which molecule is a free radical (odd-electron species)?

Accepted Answer

NO

Question 18

Which step is NOT part of the process for drawing covalent compound Lewis structures?

Accepted Answer

Assign oxidation states to each atom

Question 19

Which of the following best explains why elements in the third row and beyond can have expanded octets?

Accepted Answer

They have available d-subshells for bonding

Question 20

Which of the following is the most stable resonance structure for PO$$_4$$^{3-}$$?

Accepted Answer

The structure with negative formal charges on the oxygen atoms and a positive formal charge on the phosphorus atom

Lewis Structures and Chemical Bonding: A Comprehensive Study Guide

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