Question 1

Which of the following statements best explains why the bond angle in water ($$\ce{H2O}) is$$ $$104.5^\circ$$ instead of $$90^\circ as $$predicted by the arrangement of $$p$$ orbitals?

Accepted Answer

The bond angle is $$104.5^\circ$$ because water has two lone pairs that repel the bonding pairs more strongly, and the oxygen atom undergoes $$sp^3$$ hybridization.

Question 2

Which molecular geometry is expected for a molecule with five electron domains and one lone pair on the central atom?

Accepted Answer

Seesaw

Question 3

A molecule of $$\ce{CO2} is $$nonpolar even though it contains polar bonds. Why?

Accepted Answer

The bond dipoles cancel each other because the molecule is linear.

Question 4

Which of the following molecules has a trigonal planar electron-domain geometry and a bent molecular geometry?

Accepted Answer

$$\ce{SO2}$$

Question 5

What is the hybridization of the central atom in $$\ce{BF3}$$?

Accepted Answer

$$sp^2$$

Question 6

Which of the following best describes a $$\sigma ($$sigma) bond?

Accepted Answer

A bond formed by head-to-head overlap of orbitals with cylindrical symmetry about the internuclear axis.

Question 7

Which of the following molecules has a central atom with $$sp^3d^2$ hybridization?

Accepted Answer

$$\ce{SF6}$$

Question 8

A molecule has four electron domains: two bonding pairs and two lone pairs. What is its molecular geometry and approximate bond angle?

Accepted Answer

Bent, $$\approx 104.5^\circ$$

Question 9

Which of the following statements about multiple bonds is correct?

Accepted Answer

A double bond consists of one $$\sigma$$ bond and one $$\pi$$ bond.

Question 10

Which of the following best explains why lone pairs compress bond angles in molecules?

Accepted Answer

Lone pairs are physically larger and exert greater repulsion than bonding pairs.

Question 11

Which of the following molecules is expected to be polar?

Accepted Answer

$$\ce{H2O}$$

Question 12

What is the electron-domain geometry and molecular geometry of $$\ce{NH3}$$?

Accepted Answer

Electron-domain geometry: tetrahedral; Molecular geometry: trigonal pyramidal

Question 13

Which of the following is true about the positions of lone pairs in a trigonal bipyramidal geometry?

Accepted Answer

Lone pairs occupy equatorial positions to minimize repulsion.

Question 14

Which hybridization is associated with a bond angle of $$120^\circ$$?

Accepted Answer

$$sp^2$$

Question 15

A molecule has six electron domains around the central atom. What is the predicted electron-domain geometry and bond angle?

Accepted Answer

Octahedral, $$90^\circ$$

Question 16

Which of the following best describes the process of hybridization?

Accepted Answer

Mixing atomic orbitals to create new orbitals of equal energy (degenerate orbitals).

Question 17

Which of the following molecules has a central atom with $$sp$$ hybridization?

Accepted Answer

$$\ce{BeCl2}$$

Question 18

Which of the following is a correct step in determining the molecular geometry of a molecule using VSEPR theory?

Accepted Answer

Draw the Lewis structure, count all electron domains, and use the arrangement of bonded atoms to determine the molecular geometry.

Question 19

Which of the following statements about $$\pi (pi) $$bonds is correct?

Accepted Answer

$$\pi$$ bonds are formed by sideways overlap of unhybridized $$p$$ orbitals.

Molecular Geometry and Bonding Theories: VSEPR, Hybridization, and Molecular Polarity

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