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

$$\text{Formal charge} = (\text{number of valence electrons}) - (\text{number of nonbonding electrons}) - (\frac{1}{2} \times \text{number of bonding electrons})$$

Question 1

Which of the following best describes the difference between ionic and covalent bonding?

Accepted Answer

Ionic bonding involves the transfer of electrons from one atom to another, while covalent bonding involves the sharing of electrons between atoms.

Question 2

Which of the following compounds is most likely to have the highest lattice energy?

Accepted Answer

LiCl

Question 3

What is the formal charge on the central atom in the Lewis structure of $$\mathrm{BF_3$}$$?

Accepted Answer

$$0$$

Question 4

Which of the following statements about resonance structures is TRUE?

Accepted Answer

Resonance structures are used when one Lewis structure cannot accurately depict the electron distribution in a molecule.

Question 5

Which of the following molecules is an example of an expanded octet?

Accepted Answer

$$\mathrm{PF_5$}$$

Question 6

A molecule of ozone ($$\mathrm{O_3$}) is $$best described as:

Accepted Answer

A molecule with two identical O–O bonds due to resonance.

Question 7

Which of the following best explains why $$\mathrm{NaCl} is $$brittle and cleaves along smooth lines?

Accepted Answer

The strong electrostatic attractions in the crystal lattice cause the structure to break along planes when force is applied.

Question 8

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

Accepted Answer

$$	ext{Formal charge} = (	ext{number of valence electrons}) - (	ext{number of nonbonding electrons}) - (\frac{1}{2} 	imes 	ext{number of bonding electrons})$$

Question 9

Which of the following elements is most likely to form a molecule with fewer than eight electrons around the central atom?

Accepted Answer

Boron

Question 10

Which of the following best describes the electron configuration of ions formed by main group metals?

Accepted Answer

They lose electrons to achieve the configuration of the previous noble gas.

Question 11

Which of the following statements about bond polarity is correct?

Accepted Answer

A polar covalent bond occurs when one atom attracts electrons more strongly than the other.

Question 12

Which of the following best explains why $$\mathrm{LiF}$$ has a higher lattice energy than $$\mathrm{NaI}$$?

Accepted Answer

The smaller ionic radii in $$\mathrm{LiF}$$ result in stronger electrostatic attraction.

Question 13

Which of the following is a correct step in writing the Lewis structure for $$\mathrm{$$PCl_3$$}$$?

Accepted Answer

Sum the valence electrons from all atoms, subtracting one electron for each positive charge.

Question 14

Which of the following molecules contains a triple bond?

Accepted Answer

$$\mathrm{N_2$}$$

Question 15

Which of the following is a property of covalent compounds?

Accepted Answer

Lower melting points compared to ionic compounds

Question 16

Which of the following best describes the dominant Lewis structure for a molecule?

Accepted Answer

The structure in which atoms have formal charges closest to zero and negative charges are on the most electronegative atoms.

Question 17

Which of the following is NOT a type of exception to the octet rule?

Accepted Answer

Molecules with only single bonds

Question 18

Which of the following best describes the electron distribution in benzene ($$\mathrm{C_6H_6}$$)?

Accepted Answer

Electrons are delocalized over the entire ring, represented by resonance structures.

Question 19

Which of the following is a correct statement about the electron configuration of transition metal ions?

Accepted Answer

Transition metals lose valence s-electrons first, then d-electrons as needed.

Basic Concepts of Chemical Bonding: Ionic, Covalent, and Metallic Bonds

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