Chemical Bonding and Molecular Structure Mock Test – Class 11 Chemistry

1. A structural and molecular-orbital comparison is given below.

The row that needs correction is

2. A bonding molecular orbital is lower in energy than the combining atomic orbitals because

3. A salt is more likely to form readily when the metal has low ionization enthalpy, the non-metal has favourable electron gain enthalpy, and the ionic solid has high lattice stabilization. This combination works because

4. In the molecular orbital description of , two electrons occupy degenerate orbitals singly. The molecule is therefore

5. The SI unit of dipole moment is

6. A claim says, "In covalent bonding, each atom completely gives away its electron to the other atom." The best evaluation is that the claim

7. A common Lewis contributor of has one bond and two single bonds. Each singly bonded oxygen has three lone pairs, the double-bonded oxygen has two lone pairs, and nitrogen has no lone pair. Using , the formal charge set on nitrogen, one singly bonded oxygen, and the double-bonded oxygen is respectively

8. Six electron domains around a central atom with no lone pair give the ideal molecular shape

9. The final Lewis structure of is commonly written as because this arrangement

10. The pair of terms that describes shared and non-shared electron pairs in bonding is

11. A completed Lewis structure should be checked against the total valence electron count because

12. A molecule that can act as a Lewis acid because its central atom has an incomplete octet is

13. Assertion: A hydrogen atom can become stable in by sharing one electron pair.
Reason: Sharing one electron pair gives each hydrogen atom access to two electrons.

14. Interpret the graph description below.

The unusually high position of is best explained by

15. The electrons most directly involved in ordinary chemical bonding are

16. The most reasonable skeleton for before placing lone pairs and multiple bonds is

17. A comparison of two possible ionic compounds is given below.

The better prediction is that

18. A learner says that carbonate ion rapidly flips among three separate structures. The better statement is that carbonate ion is

19. The molecular orbital bond order is calculated using

20. In bonding terminology, the valence shell means

21. In a Lewis symbol, the dots placed around the element symbol represent

22. Use the table below for main-group atoms approaching a noble-gas-like arrangement.

The row that does not fit the usual Kossel-Lewis tendency is

23. Hydrogen is placed as the central atom in a proposed Lewis skeleton. The best reason to reject that skeleton is that hydrogen

24. In the resonance hybrid of , the three bonds are expected to have

25. Use the table below to identify the inconsistent molecular-structure record.

The row that needs correction is

26. A small highly charged cation is especially effective in producing covalent character because it has

27. Lone pairs reduce bond angles more strongly than bond pairs because lone pairs

28. Water has a bent shape because the oxygen atom has

29. For , the total valence electron count is

30. Assertion: Bond formation is often associated with a decrease in energy of the system.
Reason: A lower-energy arrangement is generally more stable than a higher-energy arrangement.

31. The percentage ionic character of a bond is sometimes estimated by

If and , the percentage ionic character is

32. van der Waals forces are best described as

33. A molecule has four identical polar bonds arranged tetrahedrally and no lone pair on the central atom. Its net dipole moment is expected to be

34. A -bond is produced by

35. For the Lewis structure of , the valence electron total is

36. Hydrogen usually follows the duplet rule rather than the octet rule because its stable outer arrangement contains

37. In the formation of from and , the donor and acceptor are respectively

38. Consider these statements about coordinate bonds.
I. The shared pair is supplied by one atom at the time of bond formation.
II. A lone-pair donor and an electron-pair acceptor are needed.
III. After formation, the coordinate bond is always weaker and visibly different from all ordinary covalent bonds in the same ion.
The valid set is

39. A note describes a particle as follows: it contains one carbon atom and two oxygen atoms chemically bonded together. The notation that best represents this particle is

40. In resonance contributors, the feature that must remain unchanged is

41. The role of a small highly charged ion in ionic bonding is best understood through

42. In , nitrogen forms three bonds and keeps one lone pair. The total number of valence electron pairs around nitrogen is

43. The hybridization and approximate bond angle around each carbon in are

44. A set of proposed resonance contributors is being checked. The proposal that must be rejected as a resonance contributor is the one in which

45. Assertion: has more covalent character than .
Reason: is larger and more polarizable than .

46. Valence bond theory successfully explains directional bonding, but one important limitation is that it does not simply explain

47. The total number of valence electrons used to draw is

48. The formal charges in one contributor of are most suitably described as

49. Use the arrangement described below. A central atom has five electron domains: three bond pairs and two lone pairs. The two lone pairs occupy equatorial positions in a trigonal bipyramidal arrangement. The molecular shape is

50. In the simple ionic model for , the electron transfer can be described as