Question 1

According to VSEPR theory, what is the primary reason for the bent shape of a water molecule?

Accepted Answer

The repulsion between the two lone pairs of electrons on the oxygen atom.

Question 2

Which of the following best describes the electron domain geometry and molecular geometry of water ($$\mathrm{H_2O}) $$according to VSEPR theory?

Accepted Answer

Electron domain geometry: tetrahedral; Molecular geometry: bent

Question 3

If water ($$\mathrm{H_2O}) $$had a linear shape instead of a bent shape, what would be the effect on its molecular polarity?

Accepted Answer

The molecule would be non-polar because the bond dipoles would cancel out.

Question 4

Which statement about lone pairs in the water molecule is correct?

Accepted Answer

There are two lone pairs of electrons on the oxygen atom.

Question 5

A chemist is comparing the bond angles in water ($$\mathrm{H_2O}) $$and methane ($$\mathrm{CH_4$}). $$Which statement is correct based on VSEPR theory?

Accepted Answer

The bond angle in water is less than in methane due to the presence of lone pairs on oxygen.

Question 6

Which of the following best explains why the VSEPR theory is useful in chemistry?

Accepted Answer

It predicts the three-dimensional geometry and polarity of molecules.

Question 7

Which of the following is a direct consequence of the bent shape of the water molecule?

Accepted Answer

Water is a polar molecule.

Question 8

Given that the oxygen atom in water has four electron groups, how many of these are bonding pairs?

Accepted Answer

Two

Question 9

Which of the following best describes bond polarity in water?

Accepted Answer

The electrons are shared unevenly between oxygen and hydrogen.

Question 10

A student claims that the shape of a molecule is determined only by the atoms present. Which concept from VSEPR theory disproves this claim?

Accepted Answer

Lone pairs of electrons also influence molecular shape.

Question 11

Which of the following would NOT be predicted by VSEPR theory for a molecule with two bonding pairs and two lone pairs on the central atom?

Accepted Answer

A linear molecular geometry

Question 12

Which of the following is the correct Lewis structure for water ($$\mathrm{H_2O}$$)?

Accepted Answer

Oxygen atom in the center with two single bonds to hydrogen atoms and two pairs of non-bonding electrons on oxygen.

Question 13

Which of the following real-world properties of water is most directly related to its molecular polarity?

Accepted Answer

Its ability to dissolve many ionic and polar substances.

Question 14

If a molecule has three bonding pairs and one lone pair on the central atom, what is its expected molecular geometry according to VSEPR theory?

Accepted Answer

Trigonal pyramidal

Question 15

Which of the following statements about the valence shell is correct?

Accepted Answer

It is the outermost shell of an atom that contains electrons.

Question 16

A scientist is designing a new solvent and wants it to be non-polar. Based on VSEPR theory, which molecular geometry should they avoid?

Accepted Answer

Bent

Question 17

Which of the following best describes the effect of lone pairs on bond angles in molecules like water?

Accepted Answer

Lone pairs decrease the bond angle between bonding pairs.

Question 18

Which of the following is a correct application of VSEPR theory to predict the shape of ammonia ($$\mathrm{NH_3$}$$)?

Accepted Answer

Ammonia has a trigonal pyramidal shape due to one lone pair on nitrogen.

Question 19

Which of the following statements about bond dipoles in water is correct?

Accepted Answer

The bond dipoles do not cancel out, resulting in a net dipole moment.

Question 20

A molecule has the formula $$\mathrm{AB_2$}$$ and two lone pairs on the central atom. What is its molecular geometry according to VSEPR theory?

Accepted Answer

Bent

Molecular Shape of Water and VSEPR Theory

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