Question 1

Which of the following statements best describes the difference between a polar covalent bond and a nonpolar covalent bond?

Accepted Answer

A polar covalent bond occurs when the difference in electronegativity between two atoms is between 0.5 and 1.9.

Question 2

What is the ground-state electron configuration for silicon (Si)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^2$$

Question 3

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

Accepted Answer

Carbon dioxide ($$CO_2)$$

Question 4

What is the formal charge on the oxygen atom in the hydroxide ion ($$OH^-$$)?

Accepted Answer

$$-1$$

Question 5

Which of the following best explains why fluorine is the most electronegative element?

Accepted Answer

Fluorine has the highest effective nuclear charge and the smallest atomic radius among the elements in its period.

Question 6

Which of the following molecules has a bond angle closest to $$109.5^\circ$$?

Accepted Answer

Methane ($$CH_4)$$

Question 7

Which of the following is the correct Lewis dot structure for carbon?

Accepted Answer

A 'C' symbol surrounded by four dots, one on each side.

Question 8

Which of the following functional groups is present in acetic acid?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 9

What is the hybridization of the central carbon atom in formaldehyde ($$CH_2O$$)?

Accepted Answer

$$sp^2$$

Question 10

Which of the following best describes the bonding in ammonia ($$NH_3$$)?

Accepted Answer

The nitrogen atom is $$sp^3$$ hybridized with bond angles slightly less than $$109.5^\circ$$ due to the lone pair.

Question 11

Which of the following is a valid resonance structure for the acetate ion ($$CH_3COO^-$$)?

Accepted Answer

Both oxygen atoms share the negative charge equally, with one double bond and one single bond to carbon in each structure.

Question 12

Which of the following molecules is expected to have the largest dipole moment?

Accepted Answer

Water ($$H_2O)$$

Question 13

Which of the following best describes the electron geometry and molecular geometry of $$PF_3$$?

Accepted Answer

Electron geometry: tetrahedral; Molecular geometry: trigonal pyramidal

Question 14

Which of the following statements about resonance structures is FALSE?

Accepted Answer

Resonance structures can differ in the arrangement of atoms.

Question 15

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

Accepted Answer

The presence of two lone pairs on oxygen compresses the bond angle to less than $$109.5^\circ.$$

Question 16

Which of the following is the correct order of increasing electronegativity for the elements: phosphorus (P), nitrogen (N), and carbon (C)?

Accepted Answer

P \u003c C \u003c N

Question 17

Which of the following best describes the bonding and hybridization in ethylene ($$C_2H_4$$)?

Accepted Answer

Each carbon is $$sp^2$$ hybridized, forming three sigma bonds and one pi bond.

Question 18

Which of the following is a correct statement about the octet rule and its exceptions?

Accepted Answer

Boron and aluminum can be stable with only six electrons in their valence shell.

Question 19

Which of the following best describes the difference between a primary, secondary, and tertiary alcohol?

Accepted Answer

A primary alcohol has the $$-OH$$ group attached to a carbon bonded to one other carbon; a secondary to two; a tertiary to three.

Covalent Bonding and Shapes of Molecules: Foundations of Organic Chemistry

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