Page 59 - Spotlight A+ Form 4 & 5 Chemistry KSSM

Chemistry Answer
to achieve the stable octet electron arrangement, 2.8. A
Reinforcement & Assessment of Science Process Skill positive magnesium ion, Mg is formed. Mg → Mg
2+
2+
+ 2e . A chlorine atom has an electron arrangement of
–
Observation 2.8.7. Each of two chlorine atoms accepts one electron
from a magnesium atom to achieve the stable octet
Oxide Reaction with nitric Reaction with sodium electron arrangement, 2.8.8. Two negative chloride ions,
2+
–
–
–
–
acid, HNO 3 hydroxide, NaOH Cl is formed. Cl + e → Cl One Mg ion and two Cl
ions are attracted to each other by a strong electrostatic
solution
attraction force. An ionic compound magnesium
White powder dissolved chloride, MgCl is formed.
2
Oxide P White powder cannot (b)
(K1) dissolve. to form a colourless – 2+ –
solution.
Cl Mg Cl
White powder
Oxide Q White powder cannot
(K2) dissolved to form a dissolve.
colourless solution.
White powder White powder dissolved 5.3
Oxide R dissolved to form a to form a colourless
(K3) 1. (a) A single covalent bond
colourless solution. solution.
Table 1
1. Variables: H Cl
(a) Manipulated: Types of oxide of elements in Period 3
(b) Responding: Solubility in acid and alkali.
(c) Fixed: Volume and concentration of sodium hydroxide
solution/ nitric acid Formula: HCl
2. Amphoteric Base Acid (b) Four single covalent bonds

ANSWER FORM 4 3. Q, R, P ©PAN ASIA PUBLICATIONS
H
Oxide R
Oxide P
Oxide Q
Table 2
H
H
C
4. Aluminium oxide
Chapter 5 Chemical Bonds Formula: CH H 4
(c) Two double covalent bonds
5.1
1. Chemical bonds are forces that hold atoms together to make O C O
compounds or molecules through transfer of electrons or
sharing of electrons.
2. Neon atom has achieved the stable octet electron Formula: CO 2
arrangement. It does not need to gain, lose or share 2. (a) 2.5
electrons with other atoms. (b) Covalent compounds
3. No. The electron arrangement of magnesium atom is 2.8.2. (c) NH 3
It does not achieve the stable octet electron arrangement. (d)
4. The electron arrangement of sodium atom is 2.8.1. Sodium H
atom can donate the single valence electron to achieve a
stable electron arrangement, 2.8.
5. (a) Ionic bond H N H
(b) Covalent bond
(c) Covalent bond
(d) Ionic bond
(e) Covalent bond
(f) Ionic bond 5.4
1. A hydrogen bond is a type of attraction force between a
5.2 hydrogen atom which bonded to a strongly electronegative
atom such as fluorine, oxygen or nitrogen with another
1. (a) 2.8; Y 2– electronegative atom (fluorine, oxygen or nitrogen) in other
(b) 2, W molecule.
+
2. A positive ion; Q 3+ 2. Molecules of HCl are attracted by weak Van der Waals
3. (a) A magnesium atom has an electron arrangement of attraction forces only. Less heat energy is required to
2.8.2. A magnesium atom donates 2 valence electrons overcome the weak Van der Waals attraction forces. On
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