Zaymiey

🧪 Chemistry  ·  p-Block Elements (Groups 13 & 14)  ·  NEET & JEE

Carbon exists as diamond (sp<sup>3</sup>) and graphite (sp<sup>2</sup>). The allotrope graphene is:

Answer: A single layer of graphite with exceptional electrical, mechanical, and thermal properties.

  • A A single layer of graphite with exceptional electrical, mechanical, and thermal properties
  • B A fully three-dimensional covalent network of carbon identical to diamond's structure
  • C A disordered amorphous carbon form lacking any long-range crystalline structure
  • D A closed, curved carbon sheet resembling a hollow soccer-ball-shaped sphere

Correct answer: A. A single layer of graphite with exceptional electrical, mechanical, and thermal properties

Explanation: Graphene is a single-atom-thick honeycomb lattice of sp<sup>2</sup> carbon; it is the strongest material and has the highest electron mobility known.

Carbon Allotropes: Diamond vs GraphiteDiamond (3D network)Every C is sp³, 4 strong bonds→ hardest natural substanceGraphite (layered sheets)weak van der Waals(layers slide → lubricant)Each C is sp², hexagonal sheets→ conducts electricity along sheets

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.

Read the full p-Block Elements (Groups 13 & 14) notes →