Q: A student claims that the formation of an ionic bond is always energetically favorable. Which of the following best evaluates this claim?

The claim is incorrect because the sum $$IE + EA + \text{lattice energy}$$ must be negative for the process to be energetically favorable.

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

$$\mathrm{MgO}$$

Question 3

What is the correct Lewis structure for $$\mathrm{$$CHCl_3$$} ($$chloroform)?

Accepted Answer

C is the central atom, single bonded to three Cl atoms and one H atom, with each Cl having three lone pairs.

Question 4

Which of the following statements about lattice energy is correct?

Accepted Answer

Lattice energy is the energy required to break one mole of an ionic solid into gaseous ions.

Question 5

Given the following energetics: $$IE + EA + 	ext{lattice energy} = -200\ \mathrm{kJ/mol}$$, what can you conclude about the formation of the ionic compound?

Accepted Answer

The formation is energetically favorable because the overall energy change is negative.

Question 6

Which of the following is the best definition of electronegativity?

Accepted Answer

The ability of an atom to attract electrons to itself in a chemical bond.

Question 7

Which of the following steps is NOT part of drawing a Lewis structure for a molecule?

Accepted Answer

Assign remaining electrons as lone pairs starting with the least electronegative atom.

Question 8

Which of the following molecules contains a triple bond in its Lewis structure?

Accepted Answer

$$\mathrm{N_2$}$$

Question 9

Why is it generally unfavorable to place hydrogen or halogens as the central atom in a Lewis structure?

Accepted Answer

Hydrogen can only form one bond and halogens usually form only one bond.

Question 10

Which of the following best describes a molecular formula?

Accepted Answer

It gives the actual number of atoms of each element in a molecule.

Question 11

A student claims that the formation of an ionic bond is always energetically favorable. Which of the following best evaluates this claim?

Accepted Answer

The claim is incorrect because the sum $$IE + EA + 	ext{lattice energy}$$ must be negative for the process to be energetically favorable.

Question 12

Which of the following is a correct statement about covalent bonds?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms.

Question 13

Which of the following best explains why $$\mathrm{Na_3N} is $$the correct formula for the compound formed between sodium and nitrogen?

Accepted Answer

Because sodium forms $$\mathrm{Na^+}$$ and nitrogen forms $$\mathrm{N$$^{3-}$$}$$, three sodium ions are needed to balance one nitride ion.

Question 14

Which of the following is the correct order of steps for drawing a Lewis structure?

Accepted Answer

Sum valence electrons, choose central atom, connect atoms with bonds, assign lone pairs.

Question 15

Which of the following best describes the relationship between lattice energy and the stability of an ionic compound?

Accepted Answer

Higher lattice energy means the compound is more stable.

Question 16

Which of the following is NOT a property of covalent compounds?

Accepted Answer

They conduct electricity in molten or aqueous state.

Question 17

Which of the following best explains why $$\mathrm{O_2$}$$ has a double bond in its Lewis structure?

Accepted Answer

Each oxygen atom needs to share two electrons to complete its octet.

Question 18

Which of the following is the best description of a structural formula?

Accepted Answer

It uses lines to represent covalent bonds and shows how atoms are connected.

Question 19

Which of the following is the correct total number of valence electrons for $$\mathrm{$$CHCl_3$$}$$?

Accepted Answer

$$26$$

Ionic and Covalent Bonding: lecture 11

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