1. 1
CHAPTER 5 : CHEMICAL BONDS
Formation of Compounds
Choose the correct answer from the table
1 Noble gases are ………………… gases. They exist as……………………….. gases and
are chemically unreactive . They have ………….………….. octet or ……………..………
electron …………………………..
2 Other atoms besides noble gases tend to achieve the stable electron arrangement
through the formation of …………………………
3 Two types of chemical bonds :
(i) …………………….. bond
- formed when atoms join together by transferring of electrons
(ii) …………………….. bond
- formed when atoms join together by ………………………………..of electrons
IONIC BONDS
Formation of ions
1 Underline the correct answer.
To achieve a stable electron arrangement :
(i) A metal atom (donates / accepts) electrons , forming a (positive / negative) ion
called cation .
(ii) A (non-metal / metal) atom accepts electrons , forming a (positive / negative) ion
called anion .
2 Complete the diagram below.
(a)
Sharing ionic stable chemical bonds
monoatomic arrangement inert covalent duplet

2. 2
(b)
(Refer to page 84 – 85 - F4 Chemistry text book)
Formation of ionic bonds
Fill in the blanks with the correct words.
1 Formation of ionic compound, sodium chloride ( NaCl )
 Electron arrangement of sodium atom is .............................................................
 A sodium atom ………………….one electron to achieve the ………………electron
arrangement which is 2.8.
 Sodium ion, ……..…........ is formed
 Electron arrangement of chlorine atom is…………………………………………..
 Electron from sodium atom is transferred to a …………………………….…atom
 A chlorine atom …………………………electron from sodium atom to
………………………….. the stable electron………………………which is 2.8.8
 Chloride ion,………………….. is formed
 The sodium ion, 
Na and chloride ion, 
Cl formed are ……………………..to one
another to form an ionic compound …………………….., NaCl .
 The strong ……………………………….forces between the opposite-charged ions is
called ………………………….bond.
(Refer to page 86 - F4 Chemistry text book)
2 Complete the diagram below.
2.8.1 2.8.7 ............. ...............
Sodium atom,Na Chlorine atom,Cl Sodium ion, …… Chloride ion, …..

3. 3
3
(a)
Fill in the blanks with the correct answers.
Formation of ionic compound magnesium chloride, MgCl2 .
 Electron arrangement of magnesium atom is ..................................................
 A magnesium atom ………………….two electrons to achieve the
………………electron arrangement which is, 2.8.
 Magnesium ion, ……..…........ is formed
 Electron arrangement of chlorine atom is…………………………………………
 Electrons from magnesium atom is transferred to two ………………….…atoms
 A chlorine atom …………………………electron from magnesium atom to
…………….. the stable electron …………………………which is 2.8.8.
 Chloride ion,………………….. is formed
 The magnesium ion,Mg2+
and two chloride ions, 
Cl formed are ………………to
one another to form an ionic compound …………………………., MgCl2
 The strong ……………………………….forces between the opposite-charged ions
is called …………………………..bond
(Refer to page 86 - F4 Chemistry text book)
(b) Complete the diagram below.
(Refer to page 86 - F4 Chemistry text book)
Covalent Bonds
Formation of covalent bonds
Fill in the blanks with the correct words.
1 Covalent bonds are formed when ..………………… atoms …………………….. electrons
to achieve ……………………. electron arrangements .
2 Types of covalent bonds:-
(i) …………………………………………………………………………………………………
(ii) …………………………………………………………………………………………………
(iii) …………………………………………………………………………………………………
3 A single bond is formed when …………………of electrons is shared between two atoms.
A double bond is formed when ………………..of electrons is shared between two atoms.

4. 4
A triple bond is formed when ………………….of electrons is shared between two atoms.
4 Formation of hydrogen molecules, H2 :-
 A hydrogen atom has ……valence electron, with an electron arrangement
of..…….
 It needs ……….. more electron to achieve the …………….. electron arrangement
 ………..hydrogen atoms ………………… one electron each for ………………
 Shared-paired electrons forms a …………….. bond in the hydrogen molecule, H2
 Single bond holds the two hydrogen atoms together because the shared-pair of
electrons is attracted to the………………….. of both atoms
5 Complete the diagram below.
(a)
(b) A covalent bond can be illustrated by using……………………………….
Formation of covalent bonds
1 Formation of oxygen molecules, O2 :
 An oxygen atom has …… valence electron, with an electron arrangement of…..…
 It needs ……….more electrons to achieve the …………….. electron arrangement
 …....oxygen atoms share………pairs of electrons forming a…..……………bond
2
(a)
Draw the electron arrangement for the formation of oxygen molecule.
[Proton number : O, 8 ;]
(b) Illustrate the formation of oxygen molecule using the Lewis structure.
3 Formation of a nitrogen molecule, N2 :
 A nitrogen atom has …… valence electron, with an electron arrangement ..……..

5. 5
 It needs ……… more electrons to achieve the …………….. electron arrangement
 ………..nitrogen atoms share………………pairs of electrons forming a ………………
covalent bond
4 Draw the electron arrangement for the formation of nitrogen molecule.
[Proton number : N, 7]
(b) Illustrate the formation for nitrogen molecule using the Lewis structure.
5 Draw the electron arrangements for the formation of the following ionic compounds:
[Proton number : Li, 3 ; Ca, 20 ; O, 8 ; Cl, 17 ]
(a) Lithium oxide, OLi2
(b) Calcium chloride, 2CaCl
6 Draw the electron arrangements for the formation of the following covalent compounds
[Proton number : C, 6 ; Cl, 17, : O, 8]
(a) Tetrachloromethane, CCl4
(b) Carbon dioxide molecule, CO2

6. 6
7 Complete the table below to compare the characteristics for the formation of ionic and
covalent bonds.
Ionic bond Characteristic Covalent bond
Valence electrons
Electrons involved
Elements
Non-metals atom and non
metal atoms
Electron transfer to achieve
stable electron arrangement
Bond formation
Particles
PROPERTIES OF IONIC AND COVALENT BONDING
Physical properties of ionic and covalent compounds
1. Complete the table of the properties of ionic and covalent compounds, using the words
given in the box :
Ionic compound Properties Covalent compound
Physical states at room
temperature
Melting points
Boiling points
Electrical Conductivity
Solubility in water
Solubility in organic solvent
2 Explain why ionic compounds are able to conduct electricity in aqueous solution or in
molten state but not in solid state.
……………………………………………………………………………………………………….
……………………………………………………………………………………………………….
……………………………………………………………………………………………………….
3 Explain why covalent compound do not conduct electricity in all states.
……………………………………………………………………………………………………….
……………………………………………………………………………………………………….
4 Explain why ionic compounds have higher melting points than covalent compounds.
……………………………………………………………………………………………………….
……………………………………………………………………………………………………….
………………………………………………………………………………………………………
5 Example of covalent compounds-
............................................................................................................................................
Uses of covalent compounds as solvent in our daily lives:
………..................................................................................................................................
conduct electricity in aqueous solution or molten state do not conduct electricity
low solid high insoluble soluble solid, liquid,
gas

7. 7
(Refer to page 90 - 91 - F4 Chemistry text book)
6
Atom A Atom B
(a) Write the electron arrangement for atom A.
………………………………………………………………………………………………..
(b) A and B can form a compound
(i) What type of bond holds atom A and B together?
…………………………………………………………………………………………..
(ii) What will happen to atom A during the formation of the compound with atom
B?
…………………………………………………………………………………………..
(iii) Draw the electron arrangement of the compound formed in (b)(ii).
(iv) State one physical property of the compound formed.
…………………………………………………………………………………………..
(c) Carbon atom, C, with an electron arrangement of 2.4 can combine with atom B to
form a compound.
(i) What is the molecular formula of the compound formed?
………………………………………………………………………………………….
(ii) If the relative atomic masses of carbon is 12 and B is 32, what is the relative
molecular mass of the compound in c(i).
…………………………………………………………………………………………..

8. 8
7 The diagram below shows the proton number and the nucleon number for three atoms of
elements, E, G and W. The letters used do not represent the actual symbols of the
elements.
(a) The reaction between atoms of element G and W forms an ionic compound
whereas the reaction between atoms of element E and W forms a covalent
compound.
Explain how these ionic and covalent compounds are formed.
Ionic compound
 Electron arrangement of an atom of element G is ...................................................
 Atom G ………………….one electron to achieve the ………………electron
arrangement which is 2.8
 G ion, ……..…........ is formed
 Electron arrangement of atom W is…………………………………………..
 Electron from atom G is transferred to an atom of…………………
 Atom W receives ………….electron from atom G to achieve the ……….…………….
electron arrangement which is 2.8.8
 W ion,………………….. is formed
 The G ion, ……….. and W ion, ………..formed are …………………………..to one
another to form an …….………compound, ……….
 The strong ……………………………….forces between the opposite-charged ions is
called ………………………….. bond.
Covalent bond
 Atom E has ……... valence electrons, with an electron arrangement of..……...
 It needs ……….. more electrons to achieve the …………….. electron arrangement
 One atom of E contributes four electrons for ………………
 Atom W has ………valence electrons, with an electron arrangement of…………….
 It needs ………….more electron to achieve the……………….electron arrangement
 One atom of E share a pair of electrons with ………….atoms of W
 Covalent compound of ………………is formed
12
E
6
23
G
11
35
W
17