TRB PG Assistant - Structure and bonding in homo‑ and heteronuclear molecules using VSEPR concepts Online Test (MCQ Quiz)

1. Which VSEPR postulate states that electron pairs in the valence shell of a central atom arrange themselves to minimize repulsion?

A) Electron pairs are arranged as far apart as possible. B) Electron pairs are arranged to minimize electron-electron repulsion. C) Electron pairs are arranged in a way that accounts for the geometry of the molecule. D) Electron pairs are arranged to maximize bonding interactions.

2. According to VSEPR theory, what is the predicted geometry of a molecule with two electron domains around the central atom?

A) Trigonal planar B) Tetrahedral C) Linear D) Trigonal pyramidal

3. What is the molecular geometry of a molecule like BeCl2, which has two bonding pairs and zero lone pairs on the central atom?

A) Bent B) Linear C) Trigonal planar D) Tetrahedral

4. A molecule with three electron domains around the central atom, where all are bonding pairs, will have which electron domain geometry and molecular geometry, respectively?

A) Tetrahedral, Trigonal pyramidal B) Trigonal planar, Trigonal planar C) Linear, Linear D) Trigonal planar, Bent

5. What is the molecular geometry of BF3, which has three bonding pairs and zero lone pairs on the central boron atom?

A) Bent B) Tetrahedral C) Trigonal planar D) Linear

6. Which of the following has a trigonal planar molecular geometry?

A) NH3 B) H2O C) CH4 D) BF3

7. In VSEPR theory, lone pairs occupy more space than bonding pairs. This leads to a compression of bond angles between bonding pairs.

A) True, lone pair repulsion is stronger than bonding pair repulsion. B) False, bonding pairs repel more strongly than lone pairs. C) True, but only for molecules with more than four electron domains. D) False, lone pairs and bonding pairs exert equal repulsion.

8. What is the electron domain geometry of a molecule with four electron domains around the central atom?

A) Trigonal planar B) Tetrahedral C) Linear D) Trigonal bipyramidal

9. What is the molecular geometry of CH4, which has four bonding pairs and zero lone pairs on the central carbon atom?

A) Trigonal pyramidal B) Tetrahedral C) Bent D) Square planar

10. Which molecule exhibits a tetrahedral molecular geometry?

A) NH3 B) H2O C) CH4 D) CO2

11. What is the molecular geometry of NH3 (ammonia)?

A) Tetrahedral B) Trigonal pyramidal C) Bent D) Linear

12. The bond angle in NH3 is slightly less than the ideal tetrahedral angle (109.5°) due to the presence of a lone pair on the nitrogen atom. What is the approximate bond angle?

A) 104.5° B) 107° C) 109.5° D) 120°

13. What is the molecular geometry of H2O (water)?

A) Bent B) Linear C) Tetrahedral D) Trigonal planar

14. The bond angle in H2O is approximately 104.5°. This is due to the presence of two lone pairs on the oxygen atom, which repel the bonding pairs more strongly than in ammonia.

A) True, the increased lone pair repulsion compresses the H-O-H angle. B) False, lone pairs reduce repulsion. C) True, but the angle is larger than in NH3. D) False, the bond angle is determined solely by the number of bonding pairs.

15. Which molecule has a bent molecular geometry?

A) CO2 B) SO2 C) CH4 D) BF3

16. What is the electron domain geometry for a molecule with five electron domains?

A) Tetrahedral B) Octahedral C) Trigonal bipyramidal D) Square pyramidal

17. In a trigonal bipyramidal electron domain geometry, where are the lone pairs most likely to occupy to minimize repulsion?

A) Axial positions B) Equatorial positions C) Any position equally D) They occupy bonding positions

18. What is the molecular geometry of PCl5, which has five bonding pairs and zero lone pairs?

A) See-saw B) T-shaped C) Trigonal bipyramidal D) Octahedral

19. Which molecule exhibits a see-saw molecular geometry?

A) SF4 B) XeF4 C) ClF3 D) PCl5

20. In SF4, the sulfur atom has five electron domains (four bonding, one lone pair). What is its molecular geometry?

A) Trigonal bipyramidal B) See-saw C) T-shaped D) Square planar

21. What is the molecular geometry of XeF4, which has six electron domains (four bonding, two lone pairs)?

A) Octahedral B) Square pyramidal C) Square planar D) See-saw

22. Which molecule has a T-shaped molecular geometry?

A) BrF3 B) XeF4 C) SF4 D) ClF3

23. In ClF3, the central chlorine atom has five electron domains (three bonding, two lone pairs). What is its molecular geometry?

A) Bent B) Trigonal pyramidal C) T-shaped D) See-saw

24. What is the electron domain geometry for a molecule with six electron domains?

A) Trigonal bipyramidal B) Octahedral C) Pentagonal bipyramidal D) Square antiprismatic

25. What is the molecular geometry of SF6, which has six bonding pairs and zero lone pairs?

A) Square pyramidal B) Octahedral C) Pentagonal planar D) Trigonal bipyramidal

26. Which molecule exhibits a square pyramidal molecular geometry?

A) SF6 B) XeF5- C) IF5 D) XeF4

27. In IF5, the central iodine atom has six electron domains (five bonding, one lone pair). What is its molecular geometry?

A) Octahedral B) Square pyramidal C) Square planar D) Pentagonal planar

28. The VSEPR model is primarily concerned with the arrangement of which type of electrons?

A) Core electrons B) Valence electrons C) Bonding electrons D) Lone pair electrons

29. Which of the following statements about VSEPR theory is FALSE?

A) It predicts molecular geometry based on electron domain repulsion. B) It considers both bonding pairs and lone pairs of electrons. C) It assumes all electron pairs repel each other equally. D) It is a theoretical model used to predict shapes of molecules.

30. What is the hybridization of the central atom in a molecule with tetrahedral electron domain geometry?

A) sp B) sp2 C) sp3 D) sp3d

31. The molecular geometry of CO2 is linear. This is consistent with the VSEPR model because the central carbon atom has two electron domains (two double bonds), which arrange themselves linearly.

A) True, linear arrangement minimizes repulsion for two electron domains. B) False, CO2 is a polar molecule and has a bent shape. C) True, but only if the bonds are single bonds. D) False, double bonds exert different repulsions than single bonds in VSEPR.

32. Consider a molecule with the general formula AX3E, where A is the central atom, X represents bonded atoms, and E represents a lone pair. What is its molecular geometry?

A) Trigonal planar B) Trigonal pyramidal C) Bent D) See-saw

33. Consider a molecule with the general formula AX2E2. What is its molecular geometry?

A) Linear B) Bent C) Trigonal planar D) Tetrahedral

34. Which of the following is NOT a possible molecular geometry predicted by VSEPR theory for a molecule with only single bonds?

A) Linear B) Trigonal planar C) Tetrahedral D) Pentagonal planar

35. In heteronuclear molecules, the VSEPR model is still applicable for predicting molecular geometry based on the valence electrons of the central atom and the number of bonded atoms and lone pairs.

A) True, electronegativity differences do not affect the basic VSEPR geometry predictions. B) False, VSEPR is only applicable to homonuclear molecules. C) True, but polarity considerations become more important. D) False, VSEPR is only applicable to molecules with identical atoms bonded to the central atom.

36. What is the molecular geometry of SO2?

A) Linear B) Bent C) Trigonal planar D) Trigonal pyramidal

37. The bond angle in SO2 is slightly less than 120° due to the lone pair on sulfur. This is consistent with VSEPR theory.

A) True, the lone pair compresses the bond angle. B) False, SO2 has a linear geometry. C) True, but the angle is slightly more than 120°. D) False, VSEPR does not predict bond angles for molecules with double bonds.

38. Which factor is MOST important in determining the molecular geometry according to VSEPR theory?

A) The number of valence electrons of the central atom B) The electronegativity of the bonded atoms C) The total number of electrons in the molecule D) The number of electron domains (bonding pairs and lone pairs) around the central atom

39. What is the molecular geometry of XeF2?

A) Linear B) Bent C) T-shaped D) Trigonal bipyramidal

40. In XeF2, the central xenon atom has five electron domains (two bonding, three lone pairs). The three lone pairs occupy the equatorial positions in a trigonal bipyramidal electron domain geometry, leading to a linear molecular geometry.

A) True, lone pairs prefer equatorial positions and lead to linear molecular geometry. B) False, three lone pairs would result in a bent molecular geometry. C) True, but the molecular geometry is T-shaped. D) False, lone pairs occupy axial positions in this case.

41. Which of the following is a homonuclear diatomic molecule?

A) HCl B) CO C) O2 D) HCN

42. For homonuclear diatomic molecules like O2, what is the predicted shape based on VSEPR concepts (considering only the two atoms)?

A) Linear B) Bent C) Trigonal planar D) Not applicable

43. For heteronuclear diatomic molecules like HCl, what is the predicted shape based on VSEPR concepts?

A) Linear B) Bent C) Trigonal planar D) Not applicable

44. Which of the following molecules has the greatest deviation from ideal bond angles due to lone pair repulsion?

A) CH4 B) NH3 C) H2O D) BF3

45. The VSEPR model is effective in predicting the shapes of molecules with up to how many electron domains around the central atom?

A) Four B) Five C) Six D) It is effective for any number of electron domains.

46. What is the hybridization of the central atom in a molecule with octahedral electron domain geometry?

A) sp3 B) sp3d C) sp3d2 D) d2sp3

47. In a trigonal bipyramidal geometry, bond angles between equatorial and axial positions are:

A) 90° B) 120° C) 180° D) Both 90° and 120°

48. What is the molecular geometry of the ion [PtCl4]2-?

A) Tetrahedral B) Square planar C) Trigonal planar D) Octahedral

49. The VSEPR theory is based on the principle of minimizing repulsion between electron pairs. This principle is also known as:

A) Heisenberg's Uncertainty Principle B) Pauli Exclusion Principle C) Aufbau Principle D) Bayer's Strain Theory

50. Which of the following statements about bond pairs and lone pairs is correct regarding repulsion strength?

A) Lone pair-lone pair > Lone pair-bond pair > Bond pair-bond pair B) Bond pair-bond pair > Lone pair-bond pair > Lone pair-lone pair C) Lone pair-lone pair > Bond pair-bond pair > Lone pair-bond pair D) Lone pair-bond pair > Lone pair-lone pair > Bond pair-bond pair

Structure and bonding in homo‑ and heteronuclear molecules using VSEPR concepts - Online Test

Test Results