Question 1

Which of the following statements best describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons from one atom to another, resulting in the formation of cations and anions, while covalent bonds involve the sharing of electron pairs between atoms.

Question 2

According to the VSEPR model, what is the molecular geometry of $$	ext{NH}_3$$?

Accepted Answer

Trigonal pyramidal

Question 3

Which of the following molecules is expected to be nonpolar based on its molecular geometry and bond polarity?

Accepted Answer

$$	ext{CO}_2$$

Question 4

What is the formal charge on the central atom in the Lewis structure of $$	ext{NO}_3^- ($$nitrate ion) if the structure has one double bond and two single bonds to oxygen?

Accepted Answer

$$0$$

Question 5

Which of the following compounds is most likely to have the highest melting point?

Accepted Answer

$$	ext{MgI}_2$$

Question 6

Given the electronegativity values: H = 2.1, F = 4.0, what is the bond polarity of the H–F bond?

Accepted Answer

Polar covalent

Question 7

Which of the following molecules has a dipole moment of zero?

Accepted Answer

$$	ext{CCl}_4$$

Question 8

What is the total number of valence electrons in a molecule of $$	ext{SO}_2$$?

Accepted Answer

$$20$$

Question 9

Which statement about resonance structures is correct?

Accepted Answer

Resonance structures depict different possible arrangements of electrons, but the actual molecule is a hybrid of these structures.

Question 10

Which of the following best explains why double bonds are shorter and stronger than single bonds?

Accepted Answer

Double bonds involve more shared electrons, increasing the electrostatic attraction between atoms.

Question 11

Using average bond energies, calculate the enthalpy change ($$	riangle H) $$for the reaction: $$	ext{H}_2 + 	ext{Cl}_2 ightarrow 2	ext{HCl}$$, given $$BE(	ext{H}-	ext{H}) = 436 kJ/$$mol, $$BE(	ext{Cl}-	ext{Cl}) = 243 kJ/$$mol, $$BE(	ext{H}-	ext{Cl}) = 431 kJ/$$mol.

Accepted Answer

$$	riangle H = -184 kJ$$

Question 12

Which molecule is expected to have an expanded octet in its Lewis structure?

Accepted Answer

$$	ext{SF}_6$$

Question 13

What is the molecular geometry of $$	ext{CO}_2$$ according to the VSEPR model?

Accepted Answer

Linear

Question 14

Which of the following is a correct Lewis structure for $$	ext{O}_2$$?

Accepted Answer

A structure with a double bond and four lone pairs

Question 15

Which of the following best describes the term 'formal charge'?

Accepted Answer

The charge assigned to an atom in a molecule, calculated as: $$FC = (	ext{valence electrons}) - (	ext{nonbonding electrons}) - rac{1}{2}(	ext{bonding electrons})$$

Question 16

Which of the following molecules is expected to be polar?

Accepted Answer

$$	ext{NH}_3$$

Question 17

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outermost shell.

Question 18

Which of the following is a characteristic of covalent compounds?

Accepted Answer

Usually composed of nonmetal atoms

Question 19

Which of the following best explains why $$	ext{H}_2	ext{O} is $$polar?

Accepted Answer

It has a bent geometry and the O–H bonds are polar.

Question 20

Which of the following best describes the relationship between bond order and bond length?

Accepted Answer

As bond order increases, bond length decreases.

Chemical Bonding I: Molecular Shapes and Polarity – Study Notes

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