Question 1

Which statement best describes the difference between ionic and covalent bonds according to the Lewis model?

Accepted Answer

Ionic bonds involve the transfer of electrons from a metal to a nonmetal, while covalent bonds involve the sharing of electrons between nonmetals.

Question 2

What is the correct Lewis structure for the cyanide ion, $$\mathrm{CN^-}$$?

Accepted Answer

$$[\cdot\cdot\mathrm{C}\equiv\mathrm{N}\cdot\cdot]^-$$

Question 3

Which molecule below is expected to have a bent molecular geometry?

Accepted Answer

$$\mathrm{H_2O}$$

Question 4

A molecule has three electron groups around its central atom. What is its ideal bond angle and electron geometry?

Accepted Answer

Bond angle: $$120^\circ$$, Geometry: Trigonal planar

Question 5

Which of the following molecules is nonpolar despite having polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 6

What is the main reason oil and water do not mix?

Accepted Answer

Water molecules are polar and oil molecules are nonpolar, causing them to repel each other.

Question 7

Which element is the most electronegative according to the Pauling scale?

Accepted Answer

Fluorine

Question 8

How many valence electrons are represented in the Lewis structure for phosphorus ($$\mathrm{P}$$)?

Accepted Answer

5

Question 9

Which of the following is an exception to the octet rule?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 10

What is the correct Lewis structure for the oxygen molecule ($$\mathrm{O_2$}$$)?

Accepted Answer

$$\cdot\cdot\mathrm{O}=\mathrm{O}\cdot\cdot$$

Question 11

Which of the following best explains why artificial sweeteners like aspartame taste sweet but have few or no calories?

Accepted Answer

They fit into the taste receptor's active site due to their molecular shape but are not metabolized or are metabolized with low energy yield.

Question 12

Which of the following molecules contains a triple bond in its Lewis structure?

Accepted Answer

$$\mathrm{N_2$}$$

Question 13

What is the molecular geometry of ammonia ($$\mathrm{NH_3$}$$)?

Accepted Answer

Trigonal pyramidal

Question 14

Which of the following steps is NOT part of writing a Lewis structure for a covalent compound?

Accepted Answer

Calculate the total number of electrons by summing the atomic numbers.

Question 15

Which of the following molecules is expected to have resonance structures?

Accepted Answer

$$\mathrm{SO_2$}$$

Question 16

A molecule has four electron groups around the central atom, two of which are lone pairs. What is its molecular geometry?

Accepted Answer

Bent

Question 17

Which of the following best describes the effect of electronegativity difference on bond type?

Accepted Answer

A large electronegativity difference results in an ionic bond, while a small difference results in a nonpolar covalent bond.

Question 18

Which of the following is true about free radicals?

Accepted Answer

They contain an odd number of valence electrons and are chemically unstable.

Question 19

Why does soap allow water and grease to mix?

Accepted Answer

Soap molecules have a polar head that interacts with water and a nonpolar tail that interacts with grease.

Chemical Bonding: Lewis Structures, Molecular Geometry, and Polarity

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