27/01/2026
Chemical Bonding and Intermolecular Forces မှသင်ခန်းစာများကို
ဖြေဆိုမည့် ကျောင်းသားများအတွက်
မေးခွန်းပုံစံ 5 မျိုးဖြင့် လေ့ကျင့်နိုင်ရန် ဖော်ပြပေးလိုက်ပါသည်
**Type 1: Multiple Choice Questions
1. The number of valence electrons in an atom is equal to its:
(A) Atomic number (B) Period number (C) Group number (D) Mass number [1].
2. What type of bond is formed by the transfer of electrons from a metal to a non-metal?
(A) Covalent (B) Ionic (C) Metallic (D) Hydrogen [2].
3. The necessary difference in electronegativity for two atoms to form an ionic compound is generally:
(A) < 1.0 (B) 1.2 (C) > 1.8 (D) 0 [3, 4].
4. What is the shape of a p orbital?
(A) Spherical (B) Dumbbell (C) Double-dumbbell (D) Linear [5].
5. Which intermolecular force is the strongest?
(A) London dispersion (B) Dipole-dipole (C) Hydrogen bonding (D) Ion-dipole [2].
6. The coordination number of Na+ in a sodium chloride crystal lattice is:
(A) 4 (B) 6 (C) 8 (D) 12 [4, 6].
7. Which molecule deviates from the octet rule by being electron-deficient?
(A) CH₄ (B) NH₃ (C) BF₃ (D) H₂O [7].
8. Which orbital is filled first according to the Aufbau principle?
(A) 2p (B) 3s (C) 1s (D) 2s [8, 9].
9. The repulsion of electron pairs around a central atom is the basis of:
(A) Hess's Law (B) VSEPR theory (C) Hund's Rule (D) Octet Rule [10, 11].
10. Metallic bonding is the attraction between metal nuclei and a:
(A) Sea of electrons (B) Lone pair (C) Cation (D) Anion [11, 12].
**Type 2: Fill in the Blanks**
11. _________ are the outermost shell electrons responsible for joining atoms [13].
12. The _________ states that atoms tend to gain, lose, or share electrons to have eight valence electrons [2].
13. A _________ unit cell has an atom at each corner and one in the center of the cube [14, 15].
14. Covalent bonds formed by sharing two electrons supplied by only one of the participating atoms are _________ bonds [11, 15].
15. Molecules with an unequal distribution of charge are called _________ molecules [12, 16].
16. The force between an ion and a neutral polar molecule is an _________ interaction [12, 17].
17. _________ forces are weak intermolecular forces binding molecules together [12, 17].
18. The strength of a metallic bond _________ across a period as the number of mobile electrons increases [18].
19. A _________ cubic unit cell has an atom at each corner and at the center of each face [15].
20. The _________ principle states that electrons occupy the lowest energy orbital first [8, 19].
**Type 3: True or False**
21. Ionic compounds generally conduct electricity in the solid state. [20].
22. Diamond is a giant covalent molecule. [11, 21].
23. All electrons in singly occupied orbitals must have opposite spins. [1, 8].
24. Electronegativity increases down a group in the Periodic Table. [1].
25. Water molecules are non-polar. [11, 22].
26. Hund’s rule states orbitals of equal energy are each occupied by one electron before any is doubly occupied. [19, 23].
27. Hydrogen bonding is a type of van der Waals force. [11, 24].
28. Metallic bond strength decreases as ionic size increases. [25].
29. CCl₄ has a total of 32 valence electrons. [26].
30. In the Lewis structure of CO, a triple bond is formed. [27].
**Type 4: Matching**
31. Aufbau Principle — (A) Geometry of electron pairs [8, 11].
32. VSEPR Theory — (B) Lowest energy orbital first [10, 11].
33. Ionic Bond — (C) Shared electron pair [2, 11].
34. Covalent Bond — (D) Electrostatic attraction between ions [2, 11].
35. Coordination Number — (E) Ions surrounding a central ion [6, 15].
36. London Dispersion — (F) Temporary dipole-induced dipole [2, 17].
37. Lewis Symbol — (G) Dots representing valence electrons [28, 29].
38. Metallic Bond — (H) Nuclei and sea of electrons [11, 12].
39. Polar Molecule — (I) Dipole moment [11, 30].
40. Octet Rule — (J) Stability with 8 electrons [2].
**Type 5: Short Answer and Problem Solving**
41. Describe the electronic configuration of ¹³Al. [5].
42. Draw the Lewis structure for NH₄⁺. [7].
43. Predict the molecular shape of CH₄ using VSEPR theory. [10].
44. Why do metals have high melting and boiling points? [31, 32].
45. Explain why dry ice (solid CO₂) is used as a coolant. [33].
46. Define the term "unit cell." [20].
47. How many orbitals are there in the p subshell? [5, 33].
48. Distinguish between a polar and a non-polar covalent bond. [12, 16].
49. List the three types of van der Waals forces. [11, 17].
50. Why does the melting point of metals increase from Na to Al? [18].
**Answer Keys**
1. C [1]; 2. B [2]; 3. C [3]; 4. B [5]; 5. D [2, 17]; 6. B [4, 6]; 7. C [7]; 8. C [8, 9]; 9. B [10, 11]; 10. A [11, 12].
11. Valence electrons [13]; 12. Octet rule [2]; 13. Body-centred [14, 15]; 14. Coordinate [11, 15]; 15. Polar [12, 16]; 16. Ion-dipole [12, 17]; 17. van der Waals [12, 17]; 18. Increases [18]; 19. Face-centred [15]; 20. Aufbau [8, 19].
21. False [20]; 22. True [11, 21]; 23. False [1, 8]; 24. False [1]; 25. False [11, 22]; 26. True [19, 23]; 27. False [24]; 28. True [25]; 29. True [26]; 30. True [27].
31-B; 32-A; 33-D; 34-C; 35-E; 36-F; 37-G; 38-H; 39-I; 40-J.
41. 1s² 2s² 2p⁶ 3s² 3p¹ [5]; 42. See [7]; 43. Tetrahedral [10]; 44. Strong electrostatic forces between nuclei and delocalized electrons [32]; 45. It sublimes and absorbs heat [33]; 46. Smallest repeating part of a crystal [20]; 47. Three [5, 33]; 48. Polar shares unequally, non-polar shares equally [12, 16]; 49. Dipole-dipole, Ion-dipole, London dispersion [11, 17]; 50. Increasing positive charge and delocalized electrons [18].
