Question 1

Which of the following statements best explains why the bond angle in water ($$\mathrm{H_2O}) is $$less than the ideal tetrahedral angle?

Accepted Answer

The two lone pairs on oxygen repel each other and the bonding pairs more strongly, compressing the bond angle below $$109.5^\circ.$$

Question 2

What is the molecular geometry of $$\mathrm{SF_4$}$$ and where does its lone pair reside?

Accepted Answer

Seesaw; lone pair on an equatorial position

Question 3

A molecule has three electron groups and one lone pair around its central atom. What is its molecular geometry and approximate bond angle?

Accepted Answer

Bent; $$\u003c120^\circ$$

Question 4

Which of the following molecules has a square planar molecular geometry?

Accepted Answer

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

Question 5

In the molecule $$\mathrm{NH_3$} ($$ammonia), what is the electron geometry and the molecular geometry, respectively?

Accepted Answer

Tetrahedral; trigonal pyramidal

Question 6

Which of the following best describes the effect of lone pairs on bond angles in molecules with tetrahedral electron geometry?

Accepted Answer

Lone pairs compress the bond angles between atoms, making them less than $$109.5^\circ.$$

Question 7

A molecule of $$\mathrm{$$BrF_3$$}$$ has five electron groups around the central atom, two of which are lone pairs. What is its molecular geometry?

Accepted Answer

T-shaped

Question 8

Which of the following molecules is expected to have a linear molecular geometry due to the presence of three lone pairs on the central atom?

Accepted Answer

$$\mathrm{$$XeF_2$$}$$

Question 9

Predict the geometry about each interior atom in methanol ($$\mathrm{CH_3OH}). $$What are the electron and molecular geometries around the oxygen atom?

Accepted Answer

Electron geometry: tetrahedral; molecular geometry: bent

Question 10

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

Accepted Answer

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

Question 11

A patient is exposed to $$\mathrm{CO_2$}$$ gas. Using VSEPR theory, what is the molecular geometry of $$\mathrm{CO_2$}$$ and what is the bond angle?

Accepted Answer

Linear; $$180^\circ$$

Question 12

Which of the following statements about the placement of lone pairs in a trigonal bipyramidal geometry is correct?

Accepted Answer

Lone pairs always occupy equatorial positions to minimize repulsion.

Question 13

Which of the following molecules has a bond angle closest to $$90^\circ$$?

Accepted Answer

$$\mathrm{SF_6$}$$

Question 14

A molecule has six electron groups around the central atom, two of which are lone pairs. What is its molecular geometry?

Accepted Answer

Square planar

Question 15

Which of the following best explains why $$\mathrm{$$PCl_5$$}$$ has different bond angles between axial and equatorial positions?

Accepted Answer

The axial positions are closer together, resulting in $$90^\circ$$ angles with equatorial positions, while equatorial positions are $$120^\circ$$ apart.

Question 16

In glycine, what are the molecular geometries around the labelled carbon and nitrogen atoms, respectively?

Accepted Answer

C = trigonal planar, N = trigonal pyramidal

Question 17

Which of the following is the correct order of electron group repulsions from greatest to least?

Accepted Answer

lone pair/lone pair \u003e lone pair/bonded pair \u003e bonded pair/bonded pair

Question 18

A molecule has five electron groups: three bonding pairs and two lone pairs. What is its molecular geometry and what is a real-world example?

Accepted Answer

T-shaped; $$\mathrm{$$BrF_3$$}$$

Question 19

Which of the following best describes the geometry of nitrate ion ($$\mathrm{NO_3$^-}$$)?

Accepted Answer

Trigonal planar

Chapter 10: Chemical Bonding II – Molecular Shapes and Valence Bond Theory (CHEM 1000 Study Notes)

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