Question 1

Which statement best describes the role of valence electrons in Lewis Theory?

Accepted Answer

Valence electrons play a fundamental role in chemical bonding, being transferred in ionic bonds and shared in covalent bonds.

Question 2

Which of the following is the correct Lewis symbol for a nitrogen atom?

Accepted Answer

$$\mathrm{N}$$ with 5 dots around it

Question 3

When drawing the Lewis structure for barium oxide ($$\mathrm{BaO}$$), what is the correct representation of the ions?

Accepted Answer

$$[\mathrm{Ba}]^{2+}[\mathrm{O}]^{2-}$$

Question 4

Which of the following best describes a coordinate covalent bond?

Accepted Answer

A bond where both electrons in the bond are donated by one atom.

Question 5

How many electrons are shared in a triple covalent bond?

Accepted Answer

6 electrons

Question 6

Which of the following molecules contains a polar covalent bond?

Accepted Answer

$$\mathrm{HCl}$$

Question 7

According to Slater's rules, what is the effective nuclear charge ($$Z_{\mathrm{eff}}) $$experienced by a 3p electron in phosphorus ($$Z=15$$)?

Accepted Answer

$$Z_{\mathrm{eff}} = 4.8$$

Question 8

Which statement about the octet rule is correct?

Accepted Answer

Main group elements tend to obey the octet rule, but there are exceptions such as electron-deficient and expanded octet species.

Question 9

What is the formal charge on the oxygen atom in the molecule $$\mathrm{CO}$$, given the Lewis structure $$:\mathrm{C} \equiv \mathrm{O}:$$?

Accepted Answer

+1

Question 10

Which of the following is a correct step in writing the Lewis structure for a polyatomic ion?

Accepted Answer

Subtract electrons for positive charges and add electrons for negative charges to the total valence electron count.

Question 11

For the nitronium ion ($$\mathrm{NO}_2^+$$), what is the most plausible Lewis structure?

Accepted Answer

$$\mathrm{O}=\mathrm{N}=\mathrm{O}$$

Question 12

Which of the following is NOT a resonance structure for ozone ($$\mathrm{O}_3$$)?

Accepted Answer

$$\mathrm{O}\equiv\mathrm{O}-\mathrm{O}$$

Question 13

What is the average bond order for the N-O bonds in the nitrate ion ($$\mathrm{NO}_3^-$$)?

Accepted Answer

$$1.33$$

Question 14

Which of the following molecules is an example of an exception to the octet rule due to an incomplete octet?

Accepted Answer

$$\mathrm{BF}_3$$

Question 15

Which element is most likely to form compounds with expanded octets?

Accepted Answer

Sulfur

Question 16

Which factor increases the strength of interionic forces in an ionic crystal?

Accepted Answer

Higher ionic charges and smaller ionic radii

Question 17

Which of the following best explains why the $$\mathrm{O}-\mathrm{O}$$ bond lengths in ozone ($$\mathrm{O}_3) $$are equal?

Accepted Answer

Resonance causes the electrons to be delocalized, resulting in equal bond lengths.

Question 18

Which molecule is most likely to be nonpolar based on its Lewis structure and electronegativity values?

Accepted Answer

$$\mathrm{CO}_2$$

Question 19

What is the correct formal charge on the central nitrogen atom in nitrosyl chloride ($$\mathrm{NOCl}) $$when the most plausible Lewis structure is drawn?

Accepted Answer

0

Chapter 9: Chemical Bonding I – Lewis Theory (General Chemistry Study Notes)

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