Answer: a football-like cage.
- A a flat carbon sheet
- B a football-like cage
- C a long straight chain
- D a simple cubic block
Correct answer: B. a football-like cage
Explanation: C₆₀ is a closed cage of 20 hexagons and 12 pentagons, shaped like a football.
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.