Page 10 - Spotlight A+ Form 4 & 5 Chemistry KSSM

Form
4
Chemistry Chapter 5 Chemical Bond
6. There are two types of chemical bonds:
(a) Ionic bond Non-metal Covalent bond Non-metal
(b) Covalent bond
Figure 5.4 Sharing of electrons between atoms
of non-metal forms a covalent bond
Try Question 5 in Formative Zone 5.1
Chemical bonds are forces that hold atoms
together to make compounds or molecules through
the transfer of electrons or sharing of electrons
• Metals are placed on the left-hand side of the
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Try Question 1 in Formative Zone 5.1 Periodic Table of Elements except hydrogen.
7. An ionic bond is formed when atoms are joined • Non-metals are placed on the right-hand side of
together by transferring electrons (between the Periodic Table of Elements.
atoms of metal and non-metal).
1 18
Ionic bond 1
Metal Non-metal 2 13 14 15 16 17
2 B
3 3 4 5 6 7 8 9 10 11 12 Si
Figure 5.3 Transferring of electrons between metal 4 GeAs
atoms and non-metal atoms forms ionic bonds 5 Sb Te
8. A covalent bond is formed when atoms are 6 Po
joined together by sharing electrons (between
atoms of non-metal). 7
Metal Non-metal
Figure 5.5 The positions of metals and non-metals
in the Periodic Table of Elements
5.1

1. What is chemical bond? C1
CHAP. 2. Why neon gas, Ne does not form a compound? C2 CHAP.
5 3. Is magnesium atom, Mg stable? Why? C2 5

4. State the electron arrangement of sodium atom, Na. How does sodium atom, Na become stable?
C3
5. Determine whether the following compounds are formed by ionic bond or covalent bond. C3
(a) Potassium chloride, KCl (d) Magnesium oxide, MgO
(b) Nitrogen dioxide, NO (e) Ammonia, NH
2 3
(c) Ethane, C H (f) Copper(II) oxide, CuO
2 6
5.2 Ionic Bond
2. A metal atom of Group 1 will donate one valence
Formation of Ions electron to form a cation with a charge of +1.
Example: Li → Li + e –
+
1. A cation is formed when a metal atom donates
its valence electrons to achieve the stable duplet Donates one +
or octet electron arrangement. electron
Li Li
X → X + ne –
n+
2.1 2
+
Lithium atom, Li Lithium ion, Li
There are more protons than electrons in a cation. Charge of 3 protons = +3 Charge of 3 protons = +3
In a neutral atom, the number of electrons is equal Charge of 3 electrons = –3 Charge of 2 electrons = –2
to the number of protons. Total charge = 0 Total charge = +1

118 5.1.1 5.2.1