Question 1

Which of the following correctly describes the bond type in carbon monoxide (CO) based on the electronegativity difference between carbon and oxygen? (C: 2.5, O: 3.5)

Accepted Answer

Polar covalent, because the electronegativity difference is between 0.5 and 1.8.

Question 2

What is the correct molecular shape and bond angle for methane ($$\mathrm{CH_4$}) $$according to VSEPR theory?

Accepted Answer

Tetrahedral, 109°

Question 3

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

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 4

Given the Lewis structure for ammonia ($$\mathrm{NH_3$}$$), how many lone pairs and bonding pairs are present on the central atom?

Accepted Answer

1 lone pair, 3 bonding pairs

Question 5

Which of the following elements exists as a diatomic molecule in its natural state?

Accepted Answer

Nitrogen ($$\mathrm{N_2$})$$

Question 6

What is the correct name for the molecular compound $$\mathrm{Cl_2O_7}$$?

Accepted Answer

Dichlorine heptoxide

Question 7

Which of the following compounds is ionic?

Accepted Answer

Barium chloride ($$\mathrm{$$BaCl_2$$})$$

Question 8

Which molecule has a bent shape with a bond angle of approximately 120°?

Accepted Answer

Sulfur dioxide ($$\mathrm{SO_2$})$$

Question 9

What is the correct formula for diphosphorus pentoxide?

Accepted Answer

$$\mathrm{P_2O_5}$$

Question 10

Which molecule is polar due to its shape, even though it has polar bonds?

Accepted Answer

Water ($$\mathrm{H_2O})$$

Question 11

Which of the following statements about the octet rule is correct?

Accepted Answer

Atoms tend to lose, gain, or share electrons until they are surrounded by eight valence electrons.

Question 12

What is the molecular shape of ammonia ($$\mathrm{NH_3$}) $$and why?

Accepted Answer

Trigonal pyramidal, because it has three bonds and one lone pair.

Question 13

Which molecule has a linear shape and bond angle of 180°?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 14

Which of the following is the correct Lewis structure for carbon monoxide ($$\mathrm{CO}$$)?

Accepted Answer

A structure with a triple bond between C and O and one lone pair on C and one on O.

Question 15

Which molecule is nonpolar because its dipoles cancel out in a symmetrical arrangement?

Accepted Answer

Carbon tetrachloride ($$\mathrm{$$CCl_4$$})$$

Question 16

What is the correct name for $$\mathrm{$$SiCl_4$$}$$?

Accepted Answer

Silicon tetrachloride

Question 17

Which molecule has a trigonal planar shape and bond angle of 120°?

Accepted Answer

Formaldehyde ($$\mathrm{H_2CO})$$

Question 18

Which of the following best describes the electronegativity trend in the periodic table?

Accepted Answer

Electronegativity increases from left to right across a period and decreases down a group.

Question 19

Which molecule is polar due to its shape and the presence of lone pairs on the central atom?

Accepted Answer

Water ($$\mathrm{H_2O})$$

Question 20

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

Accepted Answer

Hydrogen, which requires only two electrons to achieve a noble gas arrangement.

Mini-Textbook Study Guide: Molecular Compounds, Lewis Structures, Electronegativity, and Molecular Shapes

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