Question 1

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

Accepted Answer

Electronegativity decreases down a group and increases across a period.

Question 2

Given the electronegativities: $$\mathrm{Na} = 1.0$$, $$\mathrm{Cl} = 3.0$$, what type of bond is formed in $$\mathrm{NaCl}$$?

Accepted Answer

Ionic

Question 3

Which molecule is nonpolar despite having polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 4

How many valence electrons are present in a molecule of $$\mathrm{NH_3$}$$?

Accepted Answer

8

Question 5

Which of the following best explains why $$\mathrm{O_2$}$$ forms a double bond in its Lewis structure?

Accepted Answer

Each oxygen atom needs to share two electrons to complete its octet.

Question 6

A molecule has a central atom with two bonding pairs and two lone pairs of electrons. What is the molecular shape and approximate bond angle?

Accepted Answer

Bent, $$105^\circ$$

Question 7

Which of the following ions requires you to add electrons when drawing its Lewis structure?

Accepted Answer

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

Question 8

What is the total number of valence electrons in the Lewis structure of $$\mathrm{H_2O}$$?

Accepted Answer

8

Question 9

Which of the following molecules is expected to be polar?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 10

A student draws the Lewis structure for $$\mathrm{CH_2O} ($$formaldehyde). Which of the following is correct regarding the bonding and lone pairs around the central carbon atom?

Accepted Answer

Carbon has two single bonds and one double bond, with no lone pairs.

Question 11

Which of the following best describes the electron pair geometry and molecular shape of $$\mathrm{NH_3$}$$?

Accepted Answer

Tetrahedral electron geometry, trigonal pyramidal molecular shape

Question 12

Which of the following statements about bond polarity is correct?

Accepted Answer

A bond with an electronegativity difference of $$2.0 is $$considered ionic.

Question 13

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

Accepted Answer

$$\mathrm{N_2$}$$

Question 14

A molecule has a central atom with three bonding pairs and one lone pair. What is the molecular shape?

Accepted Answer

Trigonal pyramidal

Question 15

Which of the following is a correct Lewis dot structure for the fluoride ion ($$\mathrm{F^-}$$)?

Accepted Answer

$$\mathrm{F}$$ with 8 dots and a negative charge

Question 16

Which of the following best explains why $$\mathrm{$$CCl_4$$} is $$nonpolar even though it contains polar bonds?

Accepted Answer

The molecular geometry is tetrahedral, causing the bond dipoles to cancel out.

Question 17

How many total electrons are represented in the Lewis structure of the carbonate ion ($$\mathrm{CO_3$^{2-}}$$)?

Accepted Answer

24

Question 18

Which of the following is the correct order of steps for drawing a Lewis structure?

Accepted Answer

Count valence electrons, arrange atoms, connect with bonds, assign lone pairs, check octet.

Question 19

A patient is exposed to carbon monoxide ($$\mathrm{CO}). $$Which of the following best describes the bonding in $$\mathrm{CO}$$?

Accepted Answer

A triple bond between C and O, with a lone pair on each atom.

Question 20

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

Accepted Answer

$$\mathrm{CH_4$}$$

Bonding and Lewis Structures: CHM 119 Lecture 6 Study Notes

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