Many students do not know the importance on this fundamental topic known as Chemical Bondings which involves:
3 Types of Bondings:
- Ionic Bonding
- Covalent Bonding
- Metallic Bonding
And from the key concepts of the three types of bonding above, students will be further asked on the Types of Structures which includes:
- Giant Ionic/Crystal Lattice Structure (due to Ionic Bonding)
- Simple Molecular Structure (due to Covalent Bonding)
- Giant Molecular Structure (due to Covalent Bonding)
- Giant Metallic Lattice Structure (due to Metallic Bonding)
You can do a search for “Chemical Bondings” on the top right hand side to look at the numerous discussions on this topic.
Today, i would like to share with you an exam-based questions that you might be asked in Singapore GCE O-Level Pure Chemistry Examination.
Question 1:
Which of the following substance conducts electricity by the movement of free ions?
A. Copper
B. Molten aluminium oxide
C. Solid potassium chloride
D. Graphite
Suggested Solutions:
Option A: Copper is a metal and it conducts electricity due to the presence of ‘sea of delocalised valence electrons’ which are mobile. Students would need to know about Giant Metallic Lattice Structure to understand its structural properties.
Option B: Aluminium oxide is made up of aluminium ions and oxide ions which are mobile when it is in the molten state. Students would need to know about Giant Ionic/Crystal Lattice Structure to understand its structural properties.
Option C: Potassium chloride is made up of potassium ions and chloride ions BUT the ions are not mobile in the solid state because they are fixed in positions in the Giant Ionic/Crystal Lattice Structure.
Option D: Graphite does conduct electricity but it is due to unbonded delocalised valence electrons in the hexagonal layers of carbon atoms. It is not due to mobile ions! Students would need to know about Giant Molecular Structures to understand their structural properties.
As such, answer is (Option B).
For Chemical Bonding, it is important that students understand the key concepts of each type of bondings, their structural properties and the use of the correct keywords. Examiners will look at the keywords required to see if you understand your concepts. I always remind students in my O-Level Pure Chemistry Tuition Classes in Singapore.
I am sure you have learned something useful today.
Feel free to share it with your friends who need help in Basic Chemistry.
Cheers! 
silicon carbide is a solid that burns slowly, giving a solid residue and a colourless gas?
what is the solid and gas called?