Question 1

Which of the following statements best explains why ionic compounds generally have higher melting points than covalent compounds?

Accepted Answer

Ionic compounds consist of cations and anions arranged in a crystal lattice, resulting in strong electrostatic attractions.

Question 2

According to Coulomb's Law, which factor most strongly increases the lattice energy of an ionic compound?

Accepted Answer

Increasing the charge on the ions.

Question 3

Which of the following compounds would you expect to have the highest lattice energy?

Accepted Answer

CaO

Question 4

What is the correct Lewis symbol for the element nitrogen (N)?

Accepted Answer

$$\mathrm{N}\cdot\cdot\cdot\cdot\cdot$$

Question 5

Which of the following best describes the octet rule as applied to Lewis structures?

Accepted Answer

Atoms tend to gain, lose, or share electrons until they are surrounded by eight electrons in their valence shell.

Question 6

Which molecule violates the octet rule due to an incomplete octet on the central atom?

Accepted Answer

$$\mathrm{BF}_3$$

Question 7

Which of the following bonds is expected to be the most polar?

Accepted Answer

$$\mathrm{N}-\mathrm{F}$$

Question 8

What is the formal charge on the oxygen atom in the following Lewis structure of $$\mathrm{CO}_2$$: $$\mathrm{O}=\mathrm{C}=\mathrm{O}$$?

Accepted Answer

0

Question 9

Which statement about resonance structures is correct?

Accepted Answer

The actual structure of a molecule is an average of its resonance structures.

Question 10

Which of the following molecules is a free radical and therefore violates the octet rule?

Accepted Answer

$$\mathrm{NO}$$

Question 11

Which of the following best explains why $$\mathrm{PF}_5$$ can have more than eight electrons around the central atom?

Accepted Answer

Phosphorus is in the third period and can utilize d-orbitals for bonding.

Question 12

Which of the following statements about covalent bond energies is correct?

Accepted Answer

Shorter bonds tend to be stronger bonds.

Question 13

A molecule absorbs infrared radiation and its vibrational amplitude increases. What must be true about this vibrational mode?

Accepted Answer

It causes a change in the dipole moment of the molecule.

Question 14

Which of the following is the correct order of increasing electronegativity for the elements C, N, O, F?

Accepted Answer

$$\mathrm{C} \u003c \mathrm{N} \u003c \mathrm{O} \u003c \mathrm{F}$$

Question 15

Which of the following best describes the difference between electronegativity and electron affinity?

Accepted Answer

Electronegativity is a property of atoms in molecules, while electron affinity is a property of isolated atoms.

Question 16

Which of the following is NOT a limitation of Lewis structures?

Accepted Answer

They accurately predict the IR spectrum of a molecule.

Question 17

Which of the following molecules is expected to be IR active due to a change in dipole moment during vibration?

Accepted Answer

$$\mathrm{CO}_2$$

Question 18

Which of the following is the best resonance structure for a molecule, according to formal charge rules?

Accepted Answer

The structure with the fewest nonzero formal charges and negative charges on the most electronegative atom.

Question 19

Which of the following is a correct application of the curved arrow notation in resonance structures?

Accepted Answer

Moving electrons from a lone pair to form a double bond.

Chemical Bonding I – Lewis Theory (General Chemistry Study Notes)

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