Question 1

Which of the following statements best describes a covalent bond?

Accepted Answer

A two-electron bond in which the bonding atoms share valence electrons.

Question 2

How many covalent bonds can nitrogen typically form, and what is the reasoning behind this?

Accepted Answer

Nitrogen forms three bonds because it has five valence electrons and needs three more to complete its octet ($$8 - 5 = 3).$$

Question 3

Which of the following molecules has a linear geometry according to VSEPR theory?

Accepted Answer

CO$$_2$$

Question 4

What is the total number of valence electrons in the Lewis structure of CH$$_3Cl$$?

Accepted Answer

$$14$$

Question 5

Which element is an exception to the octet rule because it only needs two electrons to achieve a stable configuration?

Accepted Answer

Hydrogen

Question 6

When drawing Lewis structures for polyatomic ions, how do you account for a negative charge?

Accepted Answer

Add one electron for each negative charge.

Question 7

Which molecule is resonance-stabilized and acts as a shield against UV radiation in the upper atmosphere?

Accepted Answer

O$$_3$$

Question 8

What is the correct name for the molecule N$$_2O$_4$$?

Accepted Answer

Dinitrogen tetroxide

Question 9

Which of the following best explains why water (H$$_2O) is a $$polar molecule?

Accepted Answer

It has polar bonds and a bent shape, causing the dipoles to reinforce.

Question 10

Which formula is used to determine the number of covalent bonds an atom with four or more valence electrons will form?

Accepted Answer

$$\mathrm{Number\ of\ bonds} = 8 - \mathrm{number\ of\ valence\ electrons}$$

Question 11

Which of the following molecules has a trigonal pyramidal geometry?

Accepted Answer

NH$$_3$$

Question 12

What is the bond angle in a tetrahedral molecule such as methane (CH$$_4$$)?

Accepted Answer

$$109.5^\circ$$

Question 13

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are unequally shared, pulled toward the more electronegative atom.

Question 14

If a molecule has three groups around a central atom, what is its expected geometry and bond angle?

Accepted Answer

Trigonal planar, $$120^\circ$$

Question 15

Which of the following is true about resonance structures?

Accepted Answer

They have the same arrangement of atoms but different arrangements of electrons.

Question 16

Which molecule is nonpolar due to its geometry, even though it contains polar bonds?

Accepted Answer

CO$$_2$$

Question 17

What is the main reason elements in the third row of the periodic table (such as P and S) can have more than eight electrons around them?

Accepted Answer

They have empty d orbitals available to accept electrons.

Question 18

Which of the following is the correct Lewis structure for ethene (C$$_2H$_4$$)?

Accepted Answer

Each carbon is connected by a double bond and each has two hydrogens attached.

Question 19

Which of the following best describes the relationship between electronegativity difference and bond type?

Accepted Answer

A small or zero electronegativity difference results in a nonpolar covalent bond.

Question 20

Which of the following is the correct name for NO$$_2$$?

Accepted Answer

Nitrogen dioxide

Covalent Compounds: Structure, Bonding, and Properties

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