Answer: +4 and +2.
- A +2 and +4
- B +4 and +2
- C +2 and +2
- D +4 and +4
Correct answer: B. +4 and +2
Explanation: Tin favours +4, but by the inert-pair effect the heavier lead is more stable as +2.
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.