1. Which of the following elements is not considered a symmetry element in point group theory?
A. Mirror plane (σ)
B. Identity (E)
C. Dipole moment (μ)
D. Rotation axis (Cn)
2. Which molecule belongs to the Td point group?
A. Water (H₂O)
B. Methane (CH₄)
C. Ammonia (NH₃)
D. Ethene (C₂H₄)
3. The point group of a linear molecule with a center of inversion is:
A. C∞v
B. D∞h
C. C2v
D. Cs
4. Which of the following is true about the C2v point group?
A. It contains no mirror planes.
B. It has a C3 principal axis.
C. It contains two vertical mirror planes.
D. It has an inversion center.
5. What is the point group of the planar molecule benzene (C₆H₆)?
A. D6h
B. C6v
C. C2h
D. D3h
6. Which of the following is not a characteristic of the Oh point group?
A. Four C3 axes
B. Inversion center
C. Only one mirror plane
D. Multiple improper rotation axes
7. A molecule with only the identity operation (E) belongs to which point group?
A. C1
B. Cs
C. Ci
D. D∞h
8. Which point group does the staggered conformation of ethane belong to?
A. D3d
B. D3h
C. C2h
D. Cs
9. The presence of which operation distinguishes the D point groups from the C point groups?
A. Identity
B. Horizontal mirror plane
C. Perpendicular C2 axes
D. Inversion center
10. Which of the following molecules belongs to the C3v point group?
A. Ammonia (NH₃)
B. Carbon dioxide (CO₂)
C. Boron trifluoride (BF₃)
D. Methane (CH₄)
Answer
CBBCA CAACA