4.2 Covalent Bonding

Which of the following best describes the octet rule in covalent bonding?

A. Atoms tend to lose or gain electrons to achieve a full outer shell of 8 electrons.

B. Atoms always have 8 electrons in their outermost shell.

C. Atoms bond covalently to achieve a total of 8 atoms.

D. Atoms always share 8 electrons in a covalent bond.

Which type of covalent bond involves the sharing of six electrons between two atoms?

A. Single bond

B. Double bond

C. Triple bond

D. Quadruple bond

Which molecule is non-polar despite having polar covalent bonds?

A. H2O

B. CO2

C. NH3

D. HCl

Which of the following molecules has the highest dipole moment?

A. CH4

B. NH3

C. H2O

D. BF3

Which of the following best describes the bond in Br2?

A. Polar covalent

B. Non-polar covalent

C. Ionic

D. Metallic

a) Describe the difference between a single, double, and triple covalent bond. [3]

b) How does the strength of these bonds vary and why? [2]

a) What is meant by the term 'electronegativity'? [2]

b) How does the difference in electronegativity between two atoms determine the polarity of the bond they form? [3]

a) Explain the significance of the octet rule in covalent bonding. [3]

b) Are there any exceptions to the octet rule? Provide an example. [2]

a) Explain how the concept of hybridisation occurs in covalent bonding and provide an example. [3]

b) Describe the concept of resonance in covalent molecules and its significance. [3]

c) Discuss the effect of bond polarity on the physical properties of covalent compounds. [2]

a) Explain the concept of dipole moment in a covalent bond and how it is determined. [3]

b) Compare and contrast the characteristics of polar and non-polar covalent molecules. [3]

c) Provide an example of a molecule with polar covalent bonds and one with non-polar covalent bonds, and explain the reasons for their polarity or non-polarity. [2]