Answer: heat stability and water repellence.
- A considerable chemical reactivity
- B heat stability and water repellence
- C a purely ionic bonding nature
- D a notably strong acidity
Correct answer: B. heat stability and water repellence
Explanation: Their inert silicon–oxygen backbone gives silicones heat resistance, chemical inertness and water repellence.
Diamond's rigid 3D tetrahedral network makes it the hardest natural material, while graphite's flat hexagonal sheets are held together only by weak forces, letting them slide past each other (used as a lubricant and in pencils).
Concept context
Covers the Boron family (Group 13: B, Al) and the Carbon family (Group 14: C, Si, Ge, Sn, Pb). Key topics include Lewis acid behaviour of BF₃, borax bead test, silicates, silicones, allotropes of carbon, and trends in properties down the group.