71. Which of the following molecules is isoelectronic with O2?
A) N2
B) CO
C) F2
D) Ne
Answer: B
Explanation: CO has the same number of electrons as O2, making it isoelectronic.
72. What is the shape of the molecular orbital formed by the overlap of two d orbitals?
A) Spherical
B) Linear
C) Delta (δ)
D) Trigonal planar
Answer: C
Explanation: The overlap of two d orbitals can form delta (δ) bonds, typically found in heavier transition metals.
73. Which of the following statements is true about the σ2p molecular orbital?
A) It is a non-bonding orbital.
B) It is lower in energy than the π2p orbital.
C) It is higher in energy than the π2p orbital.
D) It has no electrons.
Answer: B
Explanation: The σ2p orbital is lower in energy than the π2p orbitals in most cases.
74. What is the primary characteristic of a covalent bond?
A) Transfer of electrons
B) Sharing of electrons
C) Formation of ions
D) Formation of metallic bonds
Answer: B
Explanation: Covalent bonds are characterized by the sharing of electron pairs between atoms.
75. Which of the following has the highest bond dissociation energy?
A) N2
B) O2
C) F2
D) H2
Answer: A
Explanation: N2 has a triple bond, resulting in the highest bond dissociation energy compared to the others.
76. In terms of molecular orbital theory, what does a bond order of 2 indicate?
A) Single bond
B) Double bond
C) Triple bond
D) No bond
Answer: B
Explanation: A bond order of 2 indicates the presence of a double bond between the atoms.
77. What molecular shape is expected for a molecule with sp hybridization?
A) Linear
B) Trigonal planar
C) Tetrahedral
D) Octahedral
Answer: A
Explanation: Molecules with sp hybridization have a linear shape with a bond angle of 180°.
78. Which of the following best describes a non-bonding molecular orbital?
A) Contains a high electron density between nuclei
B) Contributes to bond formation
C) Does not participate in bonding
D) Has a positive energy contribution
Answer: C
Explanation: Non-bonding molecular orbitals do not contribute to bond formation and typically have no net bonding interaction.
79. Which element is commonly known to form pi bonds?
A) Sodium
B) Chlorine
C) Carbon
D) Helium
Answer: C
Explanation: Carbon is well-known for its ability to form pi bonds, particularly in multiple bonds (double and triple).
80. Which molecule exhibits resonance?
A) H2O
B) CO2
C) O3
D) NH3
Answer: C
Explanation: O3 (ozone) exhibits resonance, as it has multiple valid Lewis structures that contribute to its bonding.
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