Question 1

Which of the following molecules is expected to have a polar bond but be nonpolar overall due to its molecular geometry?

Accepted Answer

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

Question 2

Which element has the highest electronegativity according to the periodic trend?

Accepted Answer

Fluorine ($$\mathrm{F})$$

Question 3

Consider the molecule ozone ($$\mathrm{O_3$}). $$Which statement about its Lewis structure is correct?

Accepted Answer

It has resonance structures with the double bond in different positions.

Question 4

Which of the following molecules is an exception to the octet rule because it has fewer than 8 electrons around its central atom?

Accepted Answer

Boron trifluoride ($$\mathrm{BF_3$})$$

Question 5

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

Accepted Answer

Triple bonds are shorter and stronger than single bonds.

Question 6

What is the molecular geometry and approximate bond angle of ammonia ($$\mathrm{NH_3$}) $$according to VSEPR theory?

Accepted Answer

Trigonal pyramidal, $$\approx 107^\circ$$

Question 7

Assign the formal charge to the central atom in the Lewis structure of nitrate ion ($$\mathrm{NO_3$^-}).$$

Accepted Answer

The central nitrogen atom has a formal charge of $$+1$$

Question 8

Which hybridization is found in the central atom of methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

$$\mathrm{sp^3$}$$

Question 9

How many sigma ($$\sigma) $$and pi ($$\pi) $$bonds are present in ethene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

5 $$\sigma$$ bonds and 1 $$\pi$$ bond

Question 10

According to molecular orbital theory, what is the bond order of the oxygen molecule ($$\mathrm{O_2$}$$)?

Accepted Answer

2

Question 11

Which diatomic molecule is predicted to be paramagnetic based on molecular orbital theory?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 12

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

Accepted Answer

Bent, $$\approx 104.5^\circ$$

Question 13

Which of the following molecules has a central atom with $$\mathrm{sp^2$}$$ hybridization?

Accepted Answer

Ethene ($$\mathrm{C_2H_4})$$

Question 14

Which molecule below exhibits resonance?

Accepted Answer

Nitrate ion ($$\mathrm{NO_3$^-})$$

Question 15

Which of the following best explains why water ($$\mathrm{H_2O}) is a $$polar molecule?

Accepted Answer

It has a bent shape and a significant electronegativity difference between H and O.

Question 16

Which molecule has a central atom with more than 8 valence electrons, violating the octet rule?

Accepted Answer

Sulfur hexafluoride ($$\mathrm{SF_6$})$$

Question 17

Which of the following statements about the effect of lone pairs on bond angles is correct?

Accepted Answer

Lone pairs decrease bond angles compared to the ideal geometry.

Question 18

In the Lewis structure of formaldehyde ($$\mathrm{CH_2O}$$), what is the hybridization of the central carbon atom?

Accepted Answer

$$\mathrm{sp^2$}$$

Question 19

A patient is exposed to carbon monoxide ($$\mathrm{CO}). $$Which statement about the bonding in $$\mathrm{CO}$$ explains its toxicity?

Accepted Answer

The triple bond and lone pair on carbon allow $$\mathrm{CO} to $$bind strongly to hemoglobin.

Question 20

Calculate the bond order for the $$\mathrm{N_2$^+}$$ ion using molecular orbital theory.

Accepted Answer

2.5

Chemical Bonding: Lewis Structures, Molecular Shapes, and Bond Theories

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