Question 1

Which statement best explains why ionic compounds like NaCl have high melting and boiling points?

Accepted Answer

Because the ions are held together by strong electrostatic attractions in a giant lattice.

Question 2

Which factor increases the lattice energy of an ionic compound?

Accepted Answer

Increasing the charge of the ions.

Question 3

According to the band theory, why are metals good conductors of electricity?

Accepted Answer

Because there is no energy gap between the valence and conduction bands, allowing electrons to move freely.

Question 4

Which of the following is an example of a coordinate (dative covalent) bond?

Accepted Answer

The bond formed when NH$$_3$$ donates a lone pair to H$$^+ to $$form NH$$_4^+.$$

Question 5

Which molecule is an exception to the octet rule because it has fewer than 8 electrons around the central atom?

Accepted Answer

BF$$_3$$

Question 6

How many bonding pairs and lone pairs are present in a water (H$$_2O) $$molecule?

Accepted Answer

2 bonding pairs and 2 lone pairs

Question 7

Which statement about resonance structures is correct?

Accepted Answer

Resonance structures differ only in the location of $$	ext{π}$$ electrons or lone pairs.

Question 8

What is the formal charge on the oxygen atom in the most stable Lewis structure of CO$$_2$$?

Accepted Answer

$$0$$

Question 9

Which of the following best describes the bonding in hydrogen chloride (HCl) compared to chlorine gas (Cl$$_2$$)?

Accepted Answer

HCl has a bond with partial ionic character due to unequal sharing of electrons.

Question 10

Which of the following molecules is non-polar despite having polar bonds?

Accepted Answer

CO$$_2$$

Question 11

Which intermolecular force is responsible for the high boiling point of methanol (CH$$_3OH$$)?

Accepted Answer

Hydrogen bonding

Question 12

Which type of hybridization is present in the central atom of methane (CH$$_4$$)?

Accepted Answer

$$sp^3$$

Question 13

What is the effect of increasing the number of branches in an alkane molecule on its boiling point?

Accepted Answer

Boiling point decreases due to weaker intermolecular forces.

Question 14

Which statement correctly describes the solubility of ionic compounds in water?

Accepted Answer

Ionic compounds dissolve in water due to hydration of ions by polar water molecules.

Question 15

Which of the following molecules will have the largest bond angle?

Accepted Answer

CH$$_4$$

Question 16

Which factor decreases the lattice energy of an ionic compound?

Accepted Answer

Increasing the size of the ions.

Question 17

Which of the following is NOT a property of metals explained by the electron-sea model?

Accepted Answer

Poor solubility in water

Question 18

Which type of intermolecular force is present between molecules of hydrogen gas (H$$_2$$)?

Accepted Answer

London dispersion forces

Question 19

Which of the following best describes the difference between a sigma ($$\sigma) $$and a pi ($$\pi) $$bond?

Accepted Answer

A $$\sigma$$ bond is formed by head-on overlap, while a $$\pi$$ bond is formed by sideways overlap.

Question 20

Which of the following molecules is most likely to form hydrogen bonds with water?

Accepted Answer

NH$$_3$$

Molecules and Molecular Structure: Chemical Bonding (Unit 6) Study Notes

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