Test Bank Docx Ch.4 Diatomic Molecules

Chapter 4: Diatomic Molecules

Test Bank

Type: multiple choice question

Title: Chapter 04 Question 01

1) How do the bond enthalpies and bond lengths for the homonuclear diatomics, H₂, Li₂, Na₂ and K₂ change as the group is descended?

Section reference: 4.1 (Table 4.1)

a. Bond lengths increase and bond enthalpies increase.

b. Bond lengths increase and bond enthalpies decrease.

c. Bond lengths decrease and bond enthalpies increase.

d. Bond lengths decrease and bond enthalpies decrease.

Type: fill-in-blank

Title: Chapter 04 Question 02

2) For a homonuclear diatomic, the bond length is _____the distance of the atomic radius.

Section reference: 4.1

a. Twice

Type: multiple response question

Title: Chapter 04 Question 03

3) In the figure below, the shape of the curve is dictated by which of the following factors? Please select all that apply.

Section reference: 4.1 (Figure 4.2)

a. At long distances there is no interaction between the atoms as the orbitals are not able to overlap.

b. At very short distances the atoms repel strongly as the positive nuclei come into close contact.

c. The equilibrium between repulsive and attractive forces generates the bond length between the atoms.

d. As the atoms become close enough together the orbitals overlap and the atoms are drawn together as bonding occurs.

Type: true-false

Title: Chapter 04 Question 04

4) The Lewis model can be used to explain the differences in bond strength of F₂, O₂ and N₂. True or false?

a. True

Section reference: 4.1 (Table 4.1), 4.3 (Figure 4.3) b. False

Section reference: 4.1 (Table 4.1), 4.3 (Figure 4.3)

Type: fill-in-blank

Title: Chapter 04 Question 05

5) According to Lewis theory, a nitrogen atom in N₂ must share _ electrons to form a stable configuration.

Section reference: 4.2

a. 3

Type: true-false

Title: Chapter 04 Question 06

06) The dot and cross diagram for ammonia (NH₃) predicts that the shape at nitrogen is linear. True or false?

a. True

Section reference: 4.2

b. False

Section reference: 4.2

Type: multiple response question

Title: Chapter 04 Question 07

7) The bonding of which of the following molecules can be explained by the Lewis model? Please select all that apply.

Section reference: 4.2

a. F₂

b. NO

c. PF₅

d. HF

Type: fill-in-blank

Title: Chapter 04 Question 08

8) ____________ species contain unpaired electrons and are affected by an external magnetic field.

Section reference: 4.2

a. Paramagnetic

Type: true-false

Title: Chapter 04 Question 09

9) The electronegativity of an s or p block species is a constant irrespective of its oxidation state. True or false?

a. True

Section reference: 4.3

b. False

Section reference: 4.3

Type: true-false

Title: Chapter 04 Question 10

10) Interhalogen compounds of the form XF exist where X is Cl, Br and I. The contribution from X⁺ F^– resonance form is more important than the contribution from the X^- F⁺ resonance form. True or false?

a. True

Section reference: 4.3

b. False

Section reference: 4.5

Type: true-false

Title: Chapter 04 Question 11

11) Valence bond theory can be used to explain the trigonal planar structure of BF₃. True or false?

a. True

Section reference: 4.5

b. False

Section reference: 4.5

Type: true-false

Title: Chapter 04 Question 12

12) It is possible for an electron in a molecular orbital to be found outside of the boundary created by the combined atomic orbitals. True or false?

a. True

Section reference: 4.7

b. False

Section reference: 4.7

Type: fill-in-blank

Title: Chapter 04 Question 13

13) A σ (sigma) orbital has __________ symmetry about the internuclear axis.

Section reference: 4.7

a. Cylindrical

Type: matching question

Title: Chapter 04 Question 14

14) Match the bond order of the dihydrogen species with the appropriate species.

Section reference: 4.8 (Figure 4.14)

a. H₂ = 1

b. H₂^– = 0.5

c. H₂^2– = 0

Type: multiple choice question

Title: Chapter 04 Question 15

15) Taking z as the internuclear axis, how would the orbital formed from the bonding combination of two d_z² orbitals be labelled?

Section reference: 4.8

a. σ_u

b. σ_g

c. π_g

d. π_u

Type: multiple response question

Title: Chapter 04 Question 16

16) The magnetic properties of O₂ are very important as they are used to monitor the presence of oxygen in places where oxygen levels are essential. Which of the follow models suggests that dioxygen should be paramagnetic? Please select all that apply.

Section reference: 4.2, 4.5, 4.10

a. The Lewis model

b. Valence bond theory

c. Molecular orbital theory

d. All of the above

Type: true-false

Title: Chapter 04 Question 17

17) Draw the molecular orbital diagram of OF⁺ to determine the bond order. OF⁺ can exist. True or False?

a. True

Section reference: 4.12

b. False

Section reference: 4.12

Type: true-false

Title: Chapter 04 Question 18

18) MgB₂ is a superconducting compound consisting of Mg²⁺ cations and B₂^2– anions. The diboride anion in this compound is diamagnetic. True or false?

a. True

Section reference: 4.11

b. False

Section reference: 4.11

Type: multiple response question

Title: Chapter 04 Question 19

19) Which of the following statements are true in relation to homonuclear diatomics? Please select all that apply.

Section reference: 4.11, 4.12

a. Any combination of two atomic orbitals can form a bonding and an antibonding molecular orbital combination.

b. For B₂, C₂ and N₂, the σ bonding combination of the p orbitals are lower in energy than the π bonding combination.

c. For O₂, the energy level order depends on independent overlap of the s orbitals and p orbitals.

d. For B₂, C₂ and N₂, the energy level order is affected by the mixing of s and p orbitals.

Type: true-false

Title: Chapter 04 Question 20

20) The same general principles apply to constructing molecular orbital diagrams for heteronuclear diatomics as for homonuclear diatomics? True or false?

a. True

Section reference: 4.12

b. False

Section reference: 4.12

Type: multiple response question

Title: Chapter 04 Question 21

21) Which of the following statements relating to the molecular orbital energy level diagram of LiH are true? Please select all that apply.

Section reference: 4.12

a. Two atomic orbitals, one from each atom, create two molecular orbitals on the LiH molecule.

b. The antibonding combination is labelled 2σ_u.

c. The 1s orbital of Li and the 1s orbital of H are used to form the molecular orbitals.

d. The out-of-phase combination has a larger contribution from the Li atomic orbital.

Type: true-false

Title: Chapter 04 Question 22

22) The wavefunction expression for the antibonding molecular orbital (1σ) in LiH is ψ_{out of phase} = N[φ_H(1s) – λφ_Li(2s)] where λ < 1. True or false?

a. True

Section reference: 4.12 , Box 4.10

b. False

Section reference: 4.12 , Box 4.10

Type: fill-in-blank

Title: Chapter 04 Question 23

23) In HF, the single bond formed between H and F by the overlap of the 1s on hydrogen with the ___ on F.

Section reference: 4.12

a. 2p_z

Type: fill-in-blank

Title: Chapter 04 Question 24

24) The orbital containing electrons and of the highest energy is known as the _____

Section reference: 4.10

a. HOMO

Type: multiple response question

Title: Chapter 04 Question 25

25) Which of the following statements relating to the diagram of CO are true? Please select all that apply.

Section reference: 4.12

a. Adding electrons to form an anion will lower the bond order.

b. CO is paramagnetic.

c. Adding electrons to form an anion will increase the bond order.

d. CO is diamagnetic.