Question 1

Which of the following best explains why the H-Cl bond in hydrogen chloride (HCl) is polar, as shown in the first image?

Accepted Answer

Chlorine has a higher electronegativity than hydrogen, causing electrons to be drawn closer to chlorine.

Question 2

Refer to the Lewis structure of BF$$_3 ($$second image). Which statement best describes why boron in BF$$_3$$ does not obey the octet rule?

Accepted Answer

Boron has only six electrons around it, which is an exception to the octet rule.

Question 3

Which of the following molecules is an example of an expanded octet, as shown in the third image?

Accepted Answer

PF$$_5$$

Question 4

Based on the formal charge calculations for CO$$_2 ($$fourth image), which Lewis structure is the dominant one?

Accepted Answer

The structure where all atoms have a formal charge of zero.

Question 5

The bond lengths in ozone (O$$_3) $$are both 1.278 Å, as shown in the fifth image. What is the best explanation for this observation?

Accepted Answer

Ozone exhibits resonance, causing the bond order to be between a single and double bond.

Question 6

What is the electron geometry and molecular geometry of CCl$$_4 ($$sixth image)?

Accepted Answer

Electron geometry: tetrahedral; Molecular geometry: tetrahedral

Question 7

Methane (CH$$_4) $$has a bond angle of 109.5° (seventh image). What is the hybridization of the central carbon atom?

Accepted Answer

$$sp^3$$

Question 8

How many sigma ($$\sigma) $$and pi ($$\pi) $$bonds are present in HCl (eighth image)?

Accepted Answer

One $$\sigma$$ bond and no $$\pi$$ bonds

Question 9

How many sigma ($$\sigma) $$and pi ($$\pi) $$bonds are present in O$$_2 ($$ninth image)?

Accepted Answer

One $$\sigma$$ bond and one $$\pi$$ bond

Question 10

How many sigma ($$\sigma) $$and pi ($$\pi) $$bonds are present in N$$_2 ($$tenth image)?

Accepted Answer

One $$\sigma$$ bond and two $$\pi$$ bonds

Question 11

In the molecule shown in the eleventh image (glycine), what is the electron geometry around the central nitrogen atom?

Accepted Answer

Tetrahedral

Question 12

Which group on the periodic table contains the elements with the highest electronegativity (twelfth image)?

Accepted Answer

Group 17 (halogens)

Question 13

Which of the following statements about bond strength and bond length is correct?

Accepted Answer

As the number of bonds between two atoms increases, the bond length decreases and the bond strength increases.

Question 14

Which molecule below is nonpolar due to its molecular geometry, despite having polar bonds?

Accepted Answer

CCl$$_4$$

Question 15

Which of the following is a resonance structure?

Accepted Answer

Ozone (O$$_3)$$

Question 16

Which of the following best describes the difference between electron geometry and molecular geometry?

Accepted Answer

Electron geometry considers all electron domains, while molecular geometry considers only the arrangement of atoms.

Question 17

Which of the following molecules has a trigonal pyramidal molecular geometry?

Accepted Answer

NH$$_3$$

Question 18

Which of the following is the correct formula for calculating the formal charge on an atom?

Accepted Answer

$$	ext{Formal charge} = 	ext{valence electrons} - \frac{1}{2}(	ext{bonding electrons}) - 	ext{nonbonding electrons}$$

Chemical Bonding and Molecular Geometry: Study Notes

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