Q: Which of the following is the correct formula for calculating bond order in molecular orbital theory?

$$\text{Bond Order} = \frac{\text{Number of bonding electrons} - \text{Number of antibonding electrons}}{2}$$

Question 1

Which of the following statements best describes the main idea behind Valence Shell Electron Pair Repulsion (VSEPR) theory?

Accepted Answer

Electron groups around a central atom arrange themselves as far apart as possible to minimize repulsion.

Question 2

What is the electronic geometry and approximate bond angle for a molecule with three electron groups around the central atom and no lone pairs?

Accepted Answer

Trigonal planar, $$120^{\circ}$$

Question 3

A molecule of ammonia ($$\mathrm{NH_3$}) $$has four electron groups (three bonding pairs and one lone pair) around the central nitrogen atom. What is its molecular geometry?

Accepted Answer

Trigonal pyramidal

Question 4

Which of the following molecules is predicted to have a bond angle closest to $$109.5^{\circ}$$?

Accepted Answer

$$\mathrm{CH_4$}$$

Question 5

How many sigma ($$\sigma) $$and pi ($$\pi) $$bonds are present in a molecule of formaldehyde ($$\mathrm{H_2CO}$$)?

Accepted Answer

3 $$\sigma$$, 1 $$\pi$$

Question 6

Which hybridization is associated with a central atom that has a tetrahedral electronic geometry?

Accepted Answer

$$sp^3$$

Question 7

What is the molecular geometry of $$\mathrm{SF_4$} ($$sulfur tetrafluoride), which has five electron groups (four bonding, one lone pair) around the central atom?

Accepted Answer

Seesaw

Question 8

Which of the following best explains why lone pairs occupy equatorial positions in a trigonal bipyramidal geometry?

Accepted Answer

Equatorial positions have larger bond angles, minimizing lone pair repulsion.

Question 9

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 10

What is the bond order of $$\mathrm{O_2$}$$ according to molecular orbital theory?

Accepted Answer

$$2$$

Question 11

Which of the following statements about molecular orbital (MO) theory is correct?

Accepted Answer

Electrons in bonding MOs are stabilizing, while electrons in antibonding MOs are destabilizing.

Question 12

Which of the following molecules is predicted to be paramagnetic based on its molecular orbital diagram?

Accepted Answer

$$\mathrm{O_2$}$$

Question 13

A molecule has four electron groups: two bonding pairs and two lone pairs. What is its molecular geometry?

Accepted Answer

Bent

Question 14

Which of the following best describes the difference between electronic geometry and molecular geometry?

Accepted Answer

Electronic geometry considers both atoms and lone pairs, while molecular geometry considers only the positions of atoms.

Question 15

Which hybridization is expected for the central atom in $$\mathrm{CO_2$}$$?

Accepted Answer

$$sp$$

Question 16

Which of the following molecules will have a square planar molecular geometry?

Accepted Answer

$$\mathrm{$$XeF_4$$}$$

Question 17

Which of the following is a consequence of pi ($$\pi) $$bonding in molecules?

Accepted Answer

Pi bonds restrict rotation around the bond axis.

Question 18

Which of the following best explains why water ($$\mathrm{H_2O}) is a $$polar molecule?

Accepted Answer

The O-H bonds are polar and the molecule is bent.

Question 19

Which of the following is the correct formula for calculating bond order in molecular orbital theory?

Accepted Answer

$$	ext{Bond Order} = \frac{	ext{Number of bonding electrons} - 	ext{Number of antibonding electrons}}{2}$$

Question 20

Which of the following best describes the effect of lone pairs on bond angles in a molecule?

Accepted Answer

Lone pairs decrease bond angles compared to the ideal geometry.

Chemical Bonding II: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory

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