006Reactive nonmetal · Group 14 · Period 2

Carbon

Carbon (C) is element 6, a reactive nonmetal in the p-block — group 14, period 2. It is a solid at room temperature with 2 electron shells (2, 4) and an atomic mass of 12.011 u.

Atomic mass: 12.01 u
Phase · STP: solid
Melting: —
Boiling: —
Electronegativity: 2.55
Density: 1.821 g/cm³

Photograph — Texas Lane, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Emission spectrum

The visible light Carbon emits when energised — its unique spectral fingerprint.

Identity

Atomic number: 6
Standard atomic weight: 12.01 u
Category: Reactive nonmetal
Group: 14
Period: 2
Block: p-block
Oxidation states: +4, +2, -4

Physical properties

Melting point: —
Boiling point: —
Density: 1.821 g/cm³
Molar heat capacity: 8.517 J/(mol·K)
Atomic radius: 170 pm
Electron affinity: 121.7763 kJ/mol

Atomic structure

6protons

6neutrons

6electrons

4valence e⁻

Noble-gas notation: [He] 2s2 2p2
Full configuration: 1s2 2s2 2p2
Electrons per shell: 2, 4

Periodic trends

Where Carbon ranks across all 118 elements.

Electronegativity2.55

Ionization energy1086.5 kJ/mol

Electron affinity121.7763 kJ/mol

Density1.821 g/cm³

Atomic radius170 pm

Ionization energies

Energy to remove each successive electron (kJ/mol).

1.1k

2.4k

4.6k

6.2k

37.8k

47.3k

Successive ionization energies (kJ/mol, log scale).

Discovery

Discovered: Ancient
Discovered by: Ancient Egypt
Named by: —
Appearance: —