Question 1

Which of the following statements best describes the trend in electronegativity across the periodic table?

Accepted Answer

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

Question 2

Which molecule below is expected to have a nonpolar covalent bond?

Accepted Answer

C-C

Question 3

Given the Lewis structure for $$\mathrm{$$PCl_3$$}$$, how many lone pairs are present on the central phosphorus atom?

Accepted Answer

1

Question 4

Which of the following elements can have an expanded octet in a stable molecule?

Accepted Answer

Phosphorus

Question 5

What is the formal charge on the nitrogen atom in the cyanide ion ($$\mathrm{CN^-}$$)? Use the formula: $$\mathrm{FC = Valence\ electrons - (1/2\ Bonding\ Electrons + Nonbonding\ Electrons)}.$$

Accepted Answer

$$0$$

Question 6

Which of the following molecules is an example of a free radical?

Accepted Answer

$$\mathrm{NO}$$

Question 7

Which of the following best describes a resonance structure?

Accepted Answer

A structure with identical arrangements of atoms but different arrangements of electrons.

Question 8

What is the bond order of the P-O bond in $$\mathrm{PO_4$^{3-}} if $$the dominant resonance structure is considered?

Accepted Answer

$$1.25$$

Question 9

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

Accepted Answer

$$\mathrm{H_2O}$$

Question 10

A molecule has three regions of electron density and one lone pair on the central atom. What is its molecular geometry?

Accepted Answer

Bent

Question 11

Which of the following statements about bond energy and bond length is correct?

Accepted Answer

A triple bond is stronger and shorter than a single bond.

Question 12

Which of the following molecules is polar?

Accepted Answer

$$\mathrm{H_2O}$$

Question 13

Which of the following is the correct order of increasing H-N-H bond angle?

Accepted Answer

$$\mathrm{NH_2$^- \u003c NH_3$ \u003c NH_4$^+}$$

Question 14

Which of the following is NOT a requirement for a molecule to be polar?

Accepted Answer

It must have an expanded octet.

Question 15

Which of the following best explains why $$\mathrm{BF_3$} is $$nonpolar even though it contains polar bonds?

Accepted Answer

The molecule is trigonal planar, and the bond dipoles cancel due to symmetry.

Question 16

Which of the following molecules or ions is an example of an incomplete octet?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 17

What is the correct formula for calculating the formal charge on an atom?

Accepted Answer

$$\mathrm{FC = Valence\ electrons - (1/2\ Bonding\ Electrons + Nonbonding\ Electrons)}$$

Question 18

Which of the following best describes the effect of lone pairs on bond angles in a molecule?

Accepted Answer

Lone pairs decrease bond angles due to increased repulsion.

Question 19

Which of the following is a correct statement about resonance structures?

Accepted Answer

Resonance structures have the same arrangement of atoms but different arrangements of electrons.

Question 20

Which of the following molecules has the shortest and strongest N-O bond?

Accepted Answer

$$\mathrm{NO_2$^+}$$

Chemical Bonding I: Lewis Structures, Molecular Shapes, and Bond Properties

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