Question 1

Which of the following statements best explains why the bond length increases from F$$_2 to I$_2 as $$shown in the image?

Accepted Answer

The atomic radius increases down the group, so the nuclei are farther apart in larger halogens.

Question 2

Given the Lewis structures for water, ammonia, and methane, which molecule has the greatest number of lone pairs on the central atom?

Accepted Answer

Water

Question 3

Which molecule shown in the dipole moment images has the largest dipole moment, and what is the main reason for this?

Accepted Answer

Water; because of its bent shape and large difference in electronegativity between H and O.

Question 4

Why does carbon dioxide (CO$$_2) $$have a dipole moment of zero, even though it contains polar bonds?

Accepted Answer

The molecule is linear, so the bond dipoles cancel each other out.

Question 5

Which of the following best describes the structure shown for sodium chloride (NaCl) in the image?

Accepted Answer

A three-dimensional ionic lattice held together by electrostatic attraction between Na$$^+$$ and Cl$$^-$$ ions.

Question 6

In the Lewis structure for SO$$_2$$, what is the formal charge on the sulfur atom if both S–O bonds are single bonds and all remaining electrons are placed as lone pairs on the oxygens?

Accepted Answer

$$+2$$

Question 7

Which of the following statements about resonance structures is correct, as illustrated by the nitrate ion (NO$$_3^-$$)?

Accepted Answer

The actual structure is a blend of all resonance forms, with all N–O bonds being equivalent.

Question 8

According to VSEPR theory, what is the molecular geometry and bond angle of methane (CH$$_4$$)?

Accepted Answer

Tetrahedral, $$109.5^\circ$$

Question 9

Which molecule has a 'seesaw' molecular shape according to VSEPR theory?

Accepted Answer

SF$$_4$$

Question 10

Which of the following best explains why water (H$$_2O) is a $$liquid at room temperature, while methane (CH$$_4) is a $$gas, despite their similar molecular masses?

Accepted Answer

Water is polar and forms strong intermolecular hydrogen bonds.

Question 11

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

Accepted Answer

CCl$$_4$$

Question 12

What is the bond angle in ammonia (NH$$_3$$), and why is it less than the ideal tetrahedral angle?

Accepted Answer

$$107^\circ$$; lone pair-bond pair repulsion is greater than bond pair-bond pair repulsion.

Question 13

Which of the following best describes the geometry and shape of xenon tetrafluoride (XeF$$_4$$)?

Accepted Answer

Octahedral geometry, square planar shape

Question 14

Which of the following statements about bond energy is correct?

Accepted Answer

Bond energy increases as more electrons are shared between atoms.

Question 15

Which of the following is true regarding the formal charge calculation for the best Lewis structure of SO$$_2$$?

Accepted Answer

The formal charges on all atoms are zero.

Question 16

Which of the following molecules has a T-shaped molecular geometry?

Accepted Answer

ClF$$_3$$

Question 17

Which of the following factors will increase the lattice energy of an ionic compound?

Accepted Answer

Decreasing the size of the ions and increasing their charges.

Question 18

Which of the following best describes the difference between geometry and shape in VSEPR theory?

Accepted Answer

Geometry includes all electron pairs; shape includes only the arrangement of atoms.

Question 19

Which molecule has a bond angle closest to $$180^\circ$$?

Accepted Answer

CO$$_2$$

Question 20

Which of the following is a correct statement about the effect of lone pairs on molecular shape?

Accepted Answer

Lone pairs cause bond angles to decrease compared to the ideal geometry.

Covalent Bonding, Molecular Structure, and VSEPR Theory: Study Notes for General Chemistry

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