Class 9th Chemistry Unit 4 Structure of Molecules

chemistry 9th notes Chapter No 4

1. Ionic compounds have:

 
 
 
 

2. Atoms react with each other because:

 
 
 
 

3. Which one of the following is an electron deficient molecule?

 
 
 
 

4. Which pair has single covalent bond?

 
 
 
 

5. The boiling point of water is:

 
 
 
 

6. In triple covalent bond, each atom contributes how many electrons?

 
 
 
 

7. The number of electrons in the valence shell of noble gases are:

 
 
 
 

8. The nature of a chemical bond can be predicted by using:

 
 
 
 

9. Which of the following do not show ions in water?  

 
 
 
 

10. Non-polar compounds are insoluble in:

 
 
 
 

11. Water has high boiling points as compared to alcohol due to:

 
 
 
 

12. The valence electrons, which are involved in chemical bonding, are termed as:

 
 
 
 

13. Which type of force is hydrogen bonding?

 
 
 
 

14. Which one of the following has lone pair of electrons?

 
 
 
 

15. If the difference of electronegativities between two elements is more than 1.7, the bond will be:

 
 
 
 

16. The boiling point of alcohol is:

 
 
 
 

17. The density of water at 0 ⁰C is:

 
 
 
 

18. How many valence shell electrons are there in Na⁺ ion?

 
 
 
 

19. Which group of the periodic table has the tendency to gain electrons?

 
 
 
 

20. Formation of NH₄+ is due to:

 
 
 
 

21. Intermolecular forces are collectively known as:

 
 
 
 

22. Hydrogen atom requires _____ electron(s) to complete its outer most shell.

 
 
 
 

23. The compounds formed by opposite charges are known as: 

 
 
 
 

24. The electronic configuration of sodium atom is:

 
 
 
 

25. Types of chemical bonds are:

 
 
 
 

26. The electronegativity value of fluorine is:     

 
 
 
 

27. Malleability is the property by virtue of which a metal can be drawn into:

 
 
 
 

28. Which one has non-polar covalent bond?

 
 
 
 

29. Hydrogen bonding is always found in:

 
 
 
 

30. Which one is responsible for the formation of metallic bonding?

 
 
 
 

31. The forces responsible for binding the atoms together in a molecule are called:

 
 
 
 

32. A covalent bond formed by two similar atoms is known as:

 
 
 
 

33. Metals are good conductors of heat and electricity in solid and liquid state due to:

 
 
 
 

34. How many electrons are there in the valence shell of sodium atom?

 
 
 
 

35. Which one has free moving electrons?

 
 
 
 

36. Which type of attractive forces are present in ionic compounds?     

 
 
 
 

37. In NH₃, the lone pair is present in:

 
 
 
 

38. At room temperature, higher molecular mass covalent compounds are: 

 
 
 
 

39. Transfer of electrons between elements result in:

 
 
 
 

40. Noble gases are non-reactive, because they do not:  

 
 
 
 

41. The atom which accepts electron pair in Dative covalent bond is called:

 
 
 
 

42. How many lone pairs are present on nitrogen in ammonia molecule?

 
 
 
 

43. Which one is a non-polar molecule?

 
 
 
 

44. A bond formed due to complete transfer of electrons from one atom to another is called

 
 
 
 

45. Which of the following molecule has a coordinate covalent bond?

 
 
 
 

46. The mobile electrons are responsible for holding the atoms of metals together, forming a/an:

 
 
 
 

47. Every atom has a natural tendency to accommodate electrons in its valence           shell:   

 
 
 
 

48. Oxygen atom has _____ electrons in its outer most shell.

 
 
 
 

49. Which of the following is an example of polar covalent compound?

 
 
 
 

50. How many electrons pair triple covalent bond has?

 
 
 
 

51. The bond(s) formed by the transfer of electrons from one atom to the other is called _______ bond.

 
 
 
 

52. The electropositive elements have the tendency to:  

 
 
 
 

53. An atom having six electrons in its valence shell will achieve noble gas electronic configuration by:

 
 
 
 

54. Atoms of various element combine by ______ electrons.

 
 
 
 

55. Attaining two electrons in the valence shell is called:

 
 
 
 

56. Atoms achieve stability by attaining electronic configuration of:

 
 
 
 

57. Covalent bond involves the:

 
 
 
 

58. Which type of bond is present between NH₃ and BF₃?

 
 
 
 

59. Transfer of electrons between atoms results in:

 
 
 
 

60. A bond pair in covalent molecules usually has:

 
 
 
 

61. In metals, the hold of nucleus over the valence shell electrons is weak due to:

 
 
 
 

62. Identify the covalent compound:

 
 
 
 

63. A covalent bond formed by the mutual sharing of two pairs of electrons between bonded atoms is called:

 
 
 
 

64. Which one of the following is the weakest force among the atoms?

 
 
 
 

65. Considering the electronic configuration of atoms which atom with the given atomic number will be the most stable one?

 
 
 
 

66. The energy required to break the chemical bond between hydrogen and chlorine atoms in 1 mole of hydrogen chloride is:

 
 
 
 

67. Dative covalent bond is also known as:

 
 
 
 

68. The difference between electronegativities of hydrogen and chlorine:

 
 
 
 

69. All the noble gases have their valence electrons:

 
 
 
 

70. During the formation of ionic bond, heat is:

 
 
 
 

71. The atom which donates electron pair in Dative covalent bond is called:

 
 
 
 

72. Identify the compound which is not soluble in water

 
 
 
 

73. How many valence shell electrons are there in group 1 elements?   

 
 
 
 

74. How many electrons are involved in triple covalent bond?

 
 
 
 

75. The electronegativity value of atoms is given by which scale?

 
 
 
 

76. Mode of reaction of an element depends upon its:

 
 
 
 

77. The formation of ionic bond between two ions is due to:

 
 
 
 

78. The melting point of NaCl is:

 
 
 
 

79. How many covalent bonds ethyne (C₂H₂) has?

 
 
 
 

80. How many electrons are involved in the formation of single covalent bond?

 
 
 
 

81. Metals have the tendency to lose electrons due to:

 
 
 
 

82. The electronegativity of hydrogen atom is:

 
 
 
 

83. Which type of covalent bond is present in nitrogen (N₂) molecule?

 
 
 
 

84. The energy required to break the intermolecular forces between one mole of liquid hydrogen chloride molecule to convert it into gas is:

 
 
 
 

85. Which of the following is an example of a covalent compound?

 
 
 
 

86. The density of ice at 0 ⁰C is:

 
 
 
 

87. If the difference of electronegativities between two elements is less than 1.7, the bond will be:

 
 
 
 

88. Which of the following is a building block of matter?

 
 
 
 

89. When an electronegative element combines with an electropositive element the type of bonding is:

 
 
 
 

90. Non-bonding pair of electrons present in an atom is called:

 
 
 
 

91. Covalent bond is most commonly found between the elements of group

 
 
 
 

92. A bond formed by the mutual sharing of an electron pair is called:

 
 
 
 

93. When intermolecular forces become dominant between atoms then result is:

 
 
 
 

94. The force of attraction between water molecules is: 

 
 
 
 

95. Identify which pair has polar covalent bonds:

 
 
 
 

96. The boiling point of NaCl is:

 
 
 
 

97. Ionic compounds are good conductors of electricity in:

 
 
 
 

98. Identify the ionic compound:

 
 
 
 

99. octet rule is:

 
 
 
 

100. Which of the following is not an ionic compound?

 
 
 
 

101. A bond formed between two non-metals is expected to be:  

 
 
 
 

102. Hydrogen and Helium follow:

 
 
 
 

103. How many electrons are involved in the formation of double covalent bond?

 
 
 
 

104. Which compound has hydrogen bonding?

 
 
 
 

105. Identify which pair has polar covalent bond.

 
 
 
 

Short Questions

Considering the electronic configuration of nitrogen atom, how many electrons are involved in bond formation and what type of covalent bond is formed?
Define a chemical bond.
Define coordinate covalent bond.
Define hydrogen bonding.
Define intermolecular forces
Define intermolecular forces; show these forces among HCl molecule.
Define ionic bond and give an example.
Define metallic bond.
Define polar covalent bond and give an example.
Describe at least two necessary conditions for the formation of a covalent bond.
Describe Lewis structure diagram
Differentiate between donor and acceptor atom.
Differentiate between lone pair and bond pair.
Differentiate between non polar and polar covalent bond. 
Does water has a polar or non-polar covalent bond? 
Draw a structure of water molecules showing hydrogen bonding.
Draw Lewis dot and cross structure of ammonia molecule.    
Give any two the characteristic properties of ionic compounds.
Give composition of epoxy.
Give the electronic configuration of carbon atom.
Give the formation of polar covalent bond in HCl molecule.
Give uses of adhesives.
How a 10% m/m sugar solution would be prepared?
How an atom can accommodate 8 electrons in the valence shell?
How can an atom complete its octet?
How do electronegativity values help us to predict the formation of a chemical bond?
How is a covalent bond formed?
How is coordinate covalent bond formed between NH₃ and BF₃?
How is coordinate covalent bond formed in NH₄⁺?
How is ionic bond formed?
How is metallic bond formed?
If repulsive forces dominate to attractive forces will a covalent bond form?
Ionic compounds are solids. Justify.
Ionic compounds conduct electricity in solution or molten form. Why?
Metals are good conductor of electricity. Why?
More electronegative elements can form bonds between themselves. Justify.
Point out the type of covalent bonds in the following molecules CH₄, C₂H₄, H₂, N₂, and O₂.
Polymers or resins used in synthetic adhesives belong to which category?
State octet and duplet rule.
What are ionic compounds? Give examples.
What are the applications of epoxy adhesives?
What are valence electrons?
What characteristic properties do the covalent compounds have? Give any two.
What do you mean by delta sign and why it develops?
What do you mean by induced dipole?
What do you mean by malleability?
What is a dipole molecule?
What is a lone pair? How many lone pairs of electrons are present on nitrogen in ammonia?
What is a triple covalent bond? Explain with an example.
What is difference between bonded and lone pair of electron and how many bonded pair of electrons are present in NH₃ molecule?
What is difference between polar and non-polar covalent bonds? Explain with one example of each.
What is meant by a chemical bond? Write its types.
What is meant by bonding electrons?
What is meant by covalent bond?
What is meant by donor and acceptor chemical specie?
What is meant by double covalent bond? Give examples.
What is meant by duplet rule?
What is meant by electronegative atom?
What is meant by hydrogen bonding?
What is meant by metallic bond?
What is meant by octet rule?
What is meant by single covalent bond? Give examples.
What is meant by Van der Waals forces?
What is the effect of electronegativity in the formation of an ionic bond?
What is the electronegativity difference between the following pair of elements (atoms). Predict the nature of the bond between them?
(a)  H and CI (b) H and Na (c) Na and I (d) K and CI
(b)  Comparing the electronegativity differences, arrange these compounds in increasing ionic strength.
What is the relationship between electronegativity and polarity?
What properties are shown by the presence of different types of chemical bonds between atoms of metals? Give any two.
What type of attractive forces exist in ionic compounds?
What type of bond exists in sodium chloride?
What type of covalent bond is formed in nitrogen molecule?
What type of elements form metallic bonds?
What type of elements have tendency of sharing of electrons?
What type of ions are formed in metal and non metals?
What types of attractive forces exist between HCl molecules?
What types of electron pairs make a molecule good donor?
When are atoms considered to be unstable?  
When are covalent compounds considered to be good conductors of electricity?
Which electrons are involved in chemical bonding?
Which elements follow duplet rule?
Which types of electrons are responsible for holdings the atoms together in metals?
Why a dipole develops in a molecule?
Why are dipole forces of attraction not found in halogen molecules?
Why are ionic compounds easily soluble in water?
Why are noble gases non-reactive in nature?
Why chlorine can accept only 1 electron?
Why do atoms follow octet rule?
Why do atoms react?
Why do coordinate covalent compounds not form ions in water?
Why does a covalent bond become polar?
Why does group 1 elements prefer to combine with group 17 elements?
Why does ice float on water?
Why does oxygen molecule not form a polar covalent bond?
Why does sodium form a chemical bond with chlorine?
Why does sodium lose an electron and attains +1 charge?
Why has water polar covalent bonds?
Why HCl has dipole-dipole forces of attraction?
Why is BF₃ electron deficient?
Why is the bond between an electropositive and an electronegative atom ionic in nature?
Why is the hold of nucleus over the outermost electrons in metals weak?
Why the covalent compounds of bigger size molecules have high melting points?
Why the electrons move freely in metals?
Why the ionic compounds have high melting and boiling points?
Write down the names of instruments with the help of which we measure the pressure.

 

Long Questions

 

Define covalent bond and write its types with one example of each.
Define covalent compounds. Describe their properties.
Define hydrogen bonding. Explain that how these forces affect the physical properties of compounds.
Define hydrogen bonding. Explain that how these forces effect the physical properties of compounds.
Explain the types of covalent bonds with at least one example of each type.
How a Coordinate Covalent Bond is formed? Explain it with two examples.
How a coordinate covalent bond is formed? Explain with examples?
How a covalent bond develops ionic character in it? Explain.
What are intermolecular forces? Compare these forces with chemical bond forces with reference to HCl molecule?
What do you know about ionic compounds? Write their properties.
What is a chemical bond and why do atoms form a chemical bond?
What is an ionic bond? Discuss the formation of ionic bond between sodium and chlorine atoms?
What is an ionic bond? Give its formation with a suitable example.
What is chemical bond? Why do atoms form chemical bonds?
What is metallic bond? Explain it with diagram.
What is metallic bond? Explain the metallic bonding with the help of a diagram.
What is octet rule? Why do atoms always struggle to attain the nearest noble gas electronic configuration?
What type of covalent bonds are formed between hydrogen, oxygen and nitrogen? Explain their bonding with dot and cross model.
Write five properties of metals.

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