Test Yourself 5.2 (Textbook) – Chemistry Form 4 Chapter 5 (Chemical Bond)

Question 1:
Aluminium atom, Al has 13 protons while fluorine atom, F has 9 protons.
(a) Write the formulae of ions formed from the two atoms respectively.

(b) Write half-equations for the formation of ions in (a).

(c) Draw the electron arrangement to show the transfer of electrons in the formation of ionic bonds in aluminium fluoride compound.


Answer:
(a) Al³⁺ and F^–

(b) Al → Al³⁺ + 3e^–
F + e^– → F^–

(c)

Question 2:
Muriate of Potash is a type of fertiliser that has a high content of potassium chloride compound. [Proton number: Cl = 17, K = 19]
(a) Write the chemical formula for potassium chloride.
(b) Describe the formation of ionic bonds in potassium chloride compound.

Answer:
(a) KCl

(b)
• The electron arrangement of potassium atom, K is 2.8.8.1. The potassium atom donates one electron to achieve a stable octet electron arrangement and K⁺ ion is formed.

• The donated electron is transferred to a chlorine atom.

• The electron arrangement of chlorine atom, Cl is 2.8.7. The chlorine atom receives one electron to form Cl^– ion with a stable octet electron arrangement.

• The potassium ion, K⁺ and chloride ion, Cl^– of opposite charges are attracted to each other by strong electrostatic attraction force.

• Potassium chloride compound, KCl is formed.