Question 1

Which of the following best explains why ionic bonds form between sodium and chlorine atoms?

Accepted Answer

Because the formation of an ionic compound is driven by lattice energy, which stabilizes the ions.

Question 2

What is the formal charge on the central oxygen atom in the Lewis structure of ozone ($$O_3) $$where the central atom forms a double bond with one terminal oxygen and a single bond with the other?

Accepted Answer

$$+1$$

Question 3

Which statement about resonance structures is correct?

Accepted Answer

The actual electronic structure is a weighted average of all valid resonance structures, called a resonance hybrid.

Question 4

Given the Lewis structure for $$NO_3$$^-$$, which criterion is most important for determining the relative importance of its resonance structures?

Accepted Answer

The structure where each atom satisfies the octet rule and negative formal charges are on the most electronegative atoms.

Question 5

What is the bond order of the bonds in ozone ($$O_3$$)?

Accepted Answer

$$1.5$$

Question 6

Which molecule violates the octet rule by having fewer than eight valence electrons?

Accepted Answer

$$BF_3$$

Question 7

What is the molecular geometry of $$NH_3$$ according to the VSEPR model?

Accepted Answer

Trigonal pyramidal

Question 8

Which of the following molecules has a bond angle closest to $$109.5^	ext{o}$$?

Accepted Answer

$$CH_4$$

Question 9

How many charge clouds surround the central atom in $$SF_4$$ and what is its molecular geometry?

Accepted Answer

Five charge clouds; seesaw geometry

Question 10

Which of the following is true about the bond dissociation energies in $$O_3$$?

Accepted Answer

Both bonds in $$O_3$$ have the same bond dissociation energy, which is intermediate between a single and double bond.

Question 11

What is the formal charge on nitrogen in the Lewis structure of $$NO$$ where nitrogen is singly bonded to oxygen and has one lone electron?

Accepted Answer

$$0$$

Question 12

Which molecule is an example of a free radical and violates the octet rule?

Accepted Answer

$$NO$$

Question 13

What is the molecular geometry and bond angle of $$H_2O$$ according to the VSEPR model?

Accepted Answer

Bent, $$104.5^	ext{o}$$

Question 14

Which of the following statements about the VSEPR model is correct?

Accepted Answer

The VSEPR model predicts molecular shape by minimizing electron-electron repulsions among charge clouds.

Question 15

Which molecule has a square planar geometry according to the VSEPR model?

Accepted Answer

$$XeF_4$$

Question 16

A molecule has two central atoms: one is tetrahedral and the other is trigonal pyramidal. Which molecule fits this description?

Accepted Answer

Methylamine ($$CH_3NH_2)$$

Question 17

Which of the following is NOT a criterion for determining the relative importance of resonance structures?

Accepted Answer

A more positive formal charge should reside on a more electronegative atom.

Question 18

What is the bond angle in a molecule with a trigonal bipyramidal geometry for the equatorial positions?

Accepted Answer

$$120^	ext{o}$$

Question 19

Which molecule has an octahedral geometry according to the VSEPR model?

Accepted Answer

$$SF_6$$

Question 20

Which of the following molecules is linear due to having two charge clouds around the central atom?

Accepted Answer

$$CO_2$$

Resonance, Formal Charge, and Molecular Shape: General Chemistry Study Notes

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