Test Session Chapter 3 Chemical bonding (Smart Syllabus 9th class)

Multiple Choice Questions 10×1=10

1 Which of the following bonds is expected to be the weakest?

A C-C

B Cl-Cl

C O-O

D F-F

2 Which among the following has a double covalent bond?

A Ethane

B Methane

C Ethylene

D Acetylene

3 When molten copper and molten zinc are mixed together, they give rise to a new substance called brass. Predict what type of bond is formed between copper and zinc:

A Coordinative covalent bond

B Ionic bond

C Metallic bond

D Covalent bond

4 Group of noble gases in periodic table is:

A G-17

B G-16

C G-18

D G-12

5 Octet Rule is attaining electrons in shell:

A 8

B 2

C 6

D 4

6 The Bond formed between G-I and G-17 is called:

A Ionic bond

B Covalent bond

C Metallic bond

D None of these

7 Example of double covalent bond is:

A O₂

B Cl₂

C CH₄

D N₂

8 Ethene is the example of:

A Single covalent bond

B Double covalent bond

C Triple covalent bond

D None of these

9 Metals have low values of:

A Electronegativity

B Ionization energy

C Density

D None of these

10 Which of the following is a property of metallic bond?

A High melting point

B Low melting point

C High electronegativity

D None of these

Short Answer Questions 15×2=30

i What type of elements lose their outer electron easily and what types of elements gain electron easily?

ii Write down dot and cross formula of HNO₃.

Hint: Show electron dot structure for nitric acid

H — O — N = O
|
O

iii How many oxides does nitrogen form. Write down the formulae of oxides? Constructed Response

iv Write trend of metallic character in group.

v Why Alkaline earth metals are less reactive than alkali-metals?

vi How will you define dipole-dipole forces of attraction?

vii Why ice floats on water?

viii How many electrons do other noble gases have in their outermost shells?

ix Which elements follow the duplet rule instead of octet rule?

x Which electrons participate in chemical reactions?

xi What is a coordinate covalent bond?

xii How do metals conduct heat and electricity?

xiii Why can metals be drawn into wires and sheets?

xiv Is aluminum an electropositive metal?

xv Which is the most electronegative element in periodic table?

Detailed Answer Questions (Answer any 2) 2×5=10

1 What is ionic bond? Explain with formation of NaCl.

Hint: Explain electron transfer between sodium and chlorine atoms

Na (2,8,1) + Cl (2,8,7) → Na⁺ (2,8) + Cl⁻ (2,8,8) → NaCl

Ionic bond formation in NaCl

2 Describe the discovery and significance of duplet and octet rules in chemical bonding.

3 Explain the concept of intermolecular forces and their types.

Types of Intermolecular Forces:

Dipole-dipole forces
Hydrogen bonding
London dispersion forces
Ion-dipole forces