6 C Carbon

Reactive Nonmetal p-block • Group 14 Solid at 298.15 K CAS: 7440-44-0

Carbon (12.011 u)

The chemical basis of all known organic life. Renowned for versatile catenation capabilities, forming stable covalent single, double, and triple bonds across diverse allotropic architectures.

Group

14 (IVA)

Period

Valence e⁻

Electronegativity

2.55

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🃏 Flashcard

Atomic & Orbital Configuration

Quantum shells, Aufbau sequence, and covalent radii.

[He] 2s² 2p²

Full Aufbau Sequence 1s² 2s² 2p²

Subshell Spin Diagram (Hund's Rule)

↑↓

Pair (2e⁻)

↑↓

Pair (2e⁻)

2p (px, py, pz)

↑ · ↑ · —

2 unpaired valence electrons

Radii & Dimensions

Van der Waals Radius170 pm

Covalent Radius (sp³)77 pm

Triple Bond Radius60 pm

Energetics & Charge

1st Ionization Energy1086.5 kJ/mol

2nd Ionization Energy2352.6 kJ/mol

Electron Affinity121.8 kJ/mol

Observed Oxidation States

-4 -2 0 +2 +4 (Main)

Physical & Thermal Properties

Macroscopic phase thresholds and thermodynamics.

NIST Standard

Sublimation / Melting Point 3823 K (3550 °C)

Boiling / Sublimation Point 5100 K (4827 °C)

Specific Heat Capacity 0.709 J/(g·K)

⚖ Density at STP 2.267 g/cm³ (Graphite) / 3.515 (Diamond)

⚡ Thermal Conductivity 119 - 2200 W/(m·K)

💎 Mohs Hardness 1.5 (Graphite) to 10.0 (Diamond)

🎯 JEE / NEET High-Yield Notes Class 11/12 NCERT

1. Catenation Supremacy: Exceptionally high C-C bond enthalpy (~348 kJ/mol) enables long chains, branched structures, and rings.

2. Hybridization States: Readily forms sp³ (tetrahedral, 109.5°), sp² (trigonal planar, 120°), and sp (linear, 180°) hybrid orbitals.

3. pπ-pπ Multiple Bonding: Due to small atomic radius, effective sideways overlap allows stable double and triple bonds.

Structural Polymorphism

Allotropes of Carbon

Distinct crystalline networks of elemental carbon

Diamond

sp³ Network

Rigid three-dimensional tetrahedral covalent lattice. Hardest natural mineral known (Mohs 10). Electrical insulator, exceptional thermal conductor.

C-C distance: 154 pm • Density: 3.51 g/cm³

Graphite

sp² Sheets

Two-dimensional planar hexagonal sheets stacked via weak Van der Waals forces. Excellent electrical conductor along basal planes; dry lubricant.

Interlayer gap: 335 pm • Density: 2.26 g/cm³

Graphene

2D Monolayer

Single layer of carbon atoms arranged in a 2D honeycomb lattice. 200× stronger than structural steel; extraordinary electron mobility.

Nobel Prize Physics 2010 • Thickness: 0.34 nm

Fullerene (C₆₀)

Buckyball

Spherical cage molecules containing 20 hexagonal and 12 pentagonal rings resembling a soccer ball. Discovered by Kroto, Curl, and Smalley.

Diameter: ~0.71 nm • Superconducting conjugates