Questions: Molecular Shapes with and without Lone Pairs
Multiple-Choice Questions: Molecular Shapes with and without Lone Pairs
1. What is the shape of a molecule with 2 bonding pairs and no lone pairs?
A) Tetrahedral
B) Bent
C) Linear
D) Trigonal planar
E) Octahedral
2. A molecule with 3 bonding pairs and no lone pairs has what shape?
A) Bent
B) Trigonal planar
C) Trigonal pyramidal
D) Tetrahedral
E) Linear
3. The shape of CH₄ is:
A) Trigonal planar
B) Bent
C) Tetrahedral
D) Linear
E) Trigonal bipyramidal
4. Which of the following molecules has a trigonal planar shape?
A) NH₃
B) H₂O
C) SO₃
D) CH₄
E) CO₂
5. What is the shape of a molecule with 4 bonding pairs and no lone pairs?
A) Tetrahedral
B) Square planar
C) Trigonal pyramidal
D) Octahedral
E) Linear
6. Which of the following molecules is linear with no lone pairs on the central atom?
A) NH₃
B) CO₂
C) H₂O
D) SO₂
E) CH₄
7. Which of the following describes the shape of a molecule with 5 bonding pairs and no lone pairs?
A) Square planar
B) See-saw
C) Trigonal bipyramidal
D) Octahedral
E) Tetrahedral
8. What is the molecular geometry of SF₆?
A) Trigonal bipyramidal
B) Octahedral
C) Square planar
D) Tetrahedral
E) Trigonal pyramidal
9. Which of the following has a square planar shape?
A) SF₆
B) BrF₃
C) XeF₄
D) PCl₅
E) H₂O
10. Which of these molecules has a trigonal pyramidal shape due to lone pairs?
A) CH₄
B) CO₂
C) NH₃
D) BeCl₂
E) SO₃
11. How many lone pairs are on the central atom in a bent molecule like H₂O?
A) 0
B) 1
C) 2
D) 3
E) 4
12. The presence of lone pairs on a central atom causes:
A) Bond angles to increase
B) No effect on geometry
C) Bond angles to decrease
D) Elongation of bonds
E) Increased polarity always
13. Which shape results from 3 bonding pairs and 1 lone pair?
A) Trigonal planar
B) Tetrahedral
C) Trigonal pyramidal
D) Bent
E) Linear
14. Which shape results from 2 bonding pairs and 2 lone pairs?
A) Linear
B) Trigonal planar
C) Trigonal pyramidal
D) Bent
E) Tetrahedral
15. What is the shape of BrF₃ with two lone pairs?
A) Trigonal planar
B) T-shaped
C) See-saw
D) Linear
E) Octahedral
16. Which of the following molecules is square pyramidal?
A) SF₆
B) BrF₅
C) XeF₄
D) PF₅
E) NH₃
17. How many regions of electron density are around the central atom in NH₃?
A) 2
B) 3
C) 4
D) 5
E) 6
18. What is the shape of a molecule with 6 electron domains and one lone pair?
A) Octahedral
B) Trigonal bipyramidal
C) Square pyramidal
D) Tetrahedral
E) Linear
19. Which molecular shape has 4 regions of electron density, 2 bonding and 2 lone pairs?
A) Linear
B) Bent
C) Trigonal pyramidal
D) Tetrahedral
E) Trigonal planar
20. What is the electron geometry of H₂O?
A) Trigonal planar
B) Linear
C) Tetrahedral
D) Trigonal pyramidal
E) Octahedral
21. What is the bond angle in a perfect tetrahedral molecule?
A) 90°
B) 180°
C) 109.5°
D) 120°
E) 104.5°
22. What effect do lone pairs have on bond angles in molecules like NH₃ or H₂O?
A) No effect
B) They increase bond angles
C) They decrease bond angles
D) They make bonds planar
E) They neutralize polarity
23. Which of the following molecules has a bent shape?
A) CH₄
B) BeCl₂
C) H₂O
D) CO₂
E) BF₃
24. What is the shape of a molecule with 3 bonding pairs and 2 lone pairs?
A) See-saw
B) T-shaped
C) Linear
D) Trigonal planar
E) Octahedral
25. Which of the following molecules has a see-saw shape?
A) CO₂
B) SO₂
C) SF₄
D) BF₃
E) CH₄
26. Which molecule has a linear shape due to 3 lone pairs and 2 bonding pairs?
A) SF₄
B) XeF₂
C) NH₃
D) H₂O
E) CH₄
27. Which molecule is T-shaped due to its electron arrangement?
A) NH₃
B) BrF₃
C) CH₄
D) CO₂
E) XeF₂
28. Which molecule has 5 electron domains, 3 bonding and 2 lone pairs?
A) PCl₅
B) BrF₃
C) XeF₄
D) CH₄
E) H₂O
29. A molecule with 6 bonding pairs and no lone pairs has what shape?
A) Tetrahedral
B) Square planar
C) Octahedral
D) Trigonal planar
E) Linear
30. A molecule with 4 electron domains and 1 lone pair has what shape?
A) Trigonal planar
B) Tetrahedral
C) Trigonal pyramidal
D) Bent
E) Linear
Answers with Explanations
1. C) 2 bonding pairs, no lone pairs → Linear
2. B) 3 bonding, no lone → Trigonal planar
3. C) CH₄ → Tetrahedral
4. C) SO₃ → Trigonal planar
5. A) 4 bonding pairs → Tetrahedral
6. B) CO₂ → Linear
7. C) 5 bonding pairs → Trigonal bipyramidal
8. B) SF₆ → Octahedral
9. C) XeF₄ → Square planar
10. C) NH₃ → Trigonal pyramidal (1 lone pair)
11. C) H₂O → 2 bonding, 2 lone pairs
12. C) Lone pairs decrease bond angles
13. C) 3 bonding, 1 lone → Trigonal pyramidal
14. D) 2 bonding, 2 lone → Bent
15. B) BrF₃ → T-shaped
16. B) BrF₅ → Square pyramidal
17. C) NH₃ → 3 bonding, 1 lone → 4 regions
18. C) 6 domains, 1 lone → Square pyramidal
19. B) 2 bonding, 2 lone → Bent
20. C) H₂O → 4 electron groups → Tetrahedral (e⁻ geometry)
21. C) 109.5° for perfect tetrahedral
22. C) Lone pairs reduce bond angles
23. C) H₂O → Bent
24. B) 3 bonding, 2 lone → T-shaped
25. C) SF₄ → See-saw
26. B) XeF₂ → Linear (3 lone, 2 bonding)
27. B) BrF₃ → T-shaped
28. B) BrF₃ → 5 domains, 2 lone pairs
29. C) 6 bonding, no lone → Octahedral
30. C) 4 domains, 1 lone → Trigonal pyramidal
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