Question 1

Which of the following ions exhibits resonance in its Lewis structure?

Accepted Answer

Carbonate, $$\mathrm{CO_3$^{2-}}$$

Question 2

Which statement best describes electronegativity?

Accepted Answer

The ability of an atom to attract electrons in a chemical bond.

Question 3

Which of the following molecules contains a polar covalent bond?

Accepted Answer

H$$_2O$$

Question 4

Given the electronegativity values: F = 4.0, O = 3.5, N = 3.0, C = 2.5, which bond is the most polar?

Accepted Answer

C–F

Question 5

Which of the following best explains why the bond angle in H$$_2O is $$less than the ideal tetrahedral angle?

Accepted Answer

The presence of lone pairs on oxygen repels the bonding pairs, decreasing the bond angle.

Question 6

Which of the following molecules violates the octet rule?

Accepted Answer

BF$$_3$$

Question 7

What is the formal charge on the central nitrogen atom in the ammonium ion ($$\mathrm{NH_4$^+}$$)?

Accepted Answer

$$+1$$

Question 8

Which of the following is the best Lewis structure for the nitrate ion ($$\mathrm{NO_3$^-}$$)?

Accepted Answer

One double bond and two single bonds with delocalized electrons (resonance).

Question 9

Using VSEPR theory, what is the molecular geometry of the carbonate ion ($$\mathrm{CO_3$^{2-}}$$)?

Accepted Answer

Trigonal planar

Question 10

Which of the following molecules exhibits resonance?

Accepted Answer

Ozone, $$\mathrm{O_3$}$$

Question 11

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two atoms.

Question 12

Which of the following ions has a formal charge of $$-1 on $$one of its oxygen atoms in its best Lewis structure?

Accepted Answer

Bicarbonate, $$\mathrm{$$HCO_3$$^-}$$

Question 13

Which of the following statements about resonance is correct?

Accepted Answer

Resonance occurs when more than one valid Lewis structure can be drawn for a molecule or ion.

Question 14

Which of the following molecules has a bond angle closest to $$120^\circ$$?

Accepted Answer

Carbonate ion, $$\mathrm{CO_3$^{2-}}$$

Question 15

Which arrow correctly shows the dipole direction in a polar covalent bond between hydrogen and chlorine?

Accepted Answer

From H to Cl

Question 16

Which of the following is true about the effect of lone pairs on molecular geometry?

Accepted Answer

Lone pairs decrease bond angles compared to the ideal geometry.

Question 17

Which of the following best describes a polar covalent bond?

Accepted Answer

A bond where electrons are shared unequally between two atoms.

Question 18

Which of the following ions contains a central atom with an expanded octet?

Accepted Answer

Sulfate, $$\mathrm{SO_4$^{2-}}$$

Question 19

Which of the following is the correct electron geometry for the ammonium ion ($$\mathrm{NH_4$^+}) $$according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 20

A patient is exposed to carbon monoxide ($$\mathrm{CO}$$), which binds to hemoglobin more strongly than oxygen. Which property of the CO molecule explains this behavior?

Accepted Answer

CO has a polar covalent bond and a lone pair on carbon, allowing strong binding to iron in hemoglobin.

Bonding, Molecular Structure, and Resonance: Study Guide for General Chemistry

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