Q: Which of the following is the correct formula for calculating the formal charge on an atom in a Lewis structure?

$$\text{Formal charge} = \text{Valence electrons} - (\text{Nonbonding electrons} + \frac{1}{2} \text{Bonding electrons})$$

Question 1

Which of the following is the correct Lewis structure for water ($$\mathrm{H_2O}$$)?

Accepted Answer

Oxygen atom in the center with two hydrogen atoms bonded, and two pairs of lone electrons on oxygen.

Question 2

Which molecule below has a polar bond but is overall nonpolar?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 3

According to VSEPR theory, what is the molecular shape of methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

Tetrahedral

Question 4

Which of the following statements best describes the relationship between electronegativity and bond polarity?

Accepted Answer

The greater the difference in electronegativity between two atoms, the more polar the bond.

Question 5

Which intermolecular force is strongest in a sample of water ($$\mathrm{H_2O}$$)?

Accepted Answer

Hydrogen bonding

Question 6

What is the molecular shape of ammonia ($$\mathrm{NH_3$}) $$according to VSEPR theory?

Accepted Answer

Trigonal pyramidal

Question 7

Which molecule below is expected to be nonpolar based on its shape and bond polarity?

Accepted Answer

$$\mathrm{$$CCl_4$$}$$

Question 8

A patient receives a medication that is highly polar. Which type of intermolecular force will most likely dominate its interactions in the bloodstream?

Accepted Answer

Dipole-dipole interactions

Question 9

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

Accepted Answer

$$\mathrm{H_2O}$$

Question 10

Which of the following best explains why $$\mathrm{CO_2$} is $$nonpolar despite having polar bonds?

Accepted Answer

The molecule is linear and the bond dipoles cancel each other out.

Question 11

Which molecule would have the highest boiling point due to intermolecular forces?

Accepted Answer

$$\mathrm{H_2O}$$

Question 12

Which of the following is the correct formula for calculating the formal charge on an atom in a Lewis structure?

Accepted Answer

$$	ext{Formal charge} = 	ext{Valence electrons} - (	ext{Nonbonding electrons} + \frac{1}{2} 	ext{Bonding electrons})$$

Question 13

Which of the following molecules can form hydrogen bonds?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 14

A molecule has a central atom with three bonding pairs and one lone pair. What is its molecular shape according to VSEPR theory?

Accepted Answer

Trigonal pyramidal

Question 15

Which of the following best describes London dispersion forces?

Accepted Answer

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

Question 16

Which molecule below would be expected to have the strongest dipole-dipole interactions?

Accepted Answer

$$\mathrm{CH_3Cl}$$

Question 17

Which of the following is a real-life consequence of molecular polarity?

Accepted Answer

Polar molecules dissolve well in water, affecting drug delivery in the body.

Question 18

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

Accepted Answer

$$\mathrm{CO_2$}$$

Question 19

Which of the following best describes the polarity of $$\mathrm{CH_4$}$$?

Accepted Answer

Nonpolar due to its symmetrical tetrahedral shape.

Question 20

Which of the following molecules would be expected to have the weakest intermolecular forces?

Accepted Answer

$$\mathrm{CH_4$}$$

Chapter 6 Study Guide: Ionic and Molecular Compounds

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