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Element 6 · Carbon (C)

Carbon Bohr model: diagram and electrons per shell

The carbon Bohr model shows a carbon atom (C) as a small nucleus with its electrons circling it in 2 shells: 2 in shell K and 4 in shell L. This page has a rotating 3D carbon Bohr model, a flat diagram, a table of the electrons in each shell and the steps to draw it yourself.

Rotate the carbon Bohr model in 3D

Drag to orbit, scroll to zoom.

This is a Bohr model of carbon (C), a simplified picture of a single carbon atom. Its nucleus holds 6 protons, and a neutral carbon atom has 6 electrons, arranged around it in 2 shells (2 in shell K and 4 in shell L).

C K · 21s2 L · 42s2 2p2

Carbon Bohr model diagram

Bohr model diagram of carbon: a nucleus of 6 protons with 6 electrons on 2 shells, 2 in shell K and 4 in shell L, each ring labelled with its shell letter.
The carbon Bohr model drawn flat: each ring is a shell, labelled with its letter, and every dot is an electron (2 in shell K and 4 in shell L).

Carbon electrons per shell

A neutral carbon atom has 6 electrons, one for each of its 6 protons. They fill the shells from the nucleus outwards: 2 in shell K and 4 in shell L.

Electrons in each shell of the carbon Bohr model
ShellShell number (n)ElectronsMost it can hold (2n²)Subshells
K1221s2
L2482s2 2p2

How the carbon Bohr model builds up, shell by shell

Watch the carbon Bohr model come together: the nucleus first, then each shell in turn, from the innermost outwards, with its electrons joining the ring. The legend names every shell and counts its electrons, so you can read off the arrangement (2 in shell K and 4 in shell L) as it forms.

Animation of the carbon Bohr model being built: a nucleus of 6 protons appears first, then each shell grows in around it and takes its electrons, giving 6 electrons on 2 shells (2 in shell K and 4 in shell L).
The carbon Bohr model built up in six seconds: the nucleus first, then each shell with its electrons, ending with 2 in shell K and 4 in shell L. Protons are red, neutrons yellow and electrons blue.

How to draw the carbon Bohr model

  1. Find the atomic number. Carbon has atomic number 6, so a neutral atom has 6 protons and 6 electrons.
  2. Draw the nucleus. Put a circle in the centre and write C in it. The 6 protons sit there with the neutrons.
  3. Draw the shells. Sketch 2 shells as rings around the nucleus. A shell holds at most 2n² electrons: 2 in the first, 8 in the second, 18 in the third and 32 in the fourth.
  4. Place the electrons. Fill from the inside out: 2 in shell K and 4 in shell L.
  5. Check the total. 2 + 4 = 6, the atomic number, so every electron is accounted for.

Atomic data for the carbon Bohr model

The numbers behind the carbon Bohr model, grouped by topic. Radii are in picometres (pm) and energies in kilojoules per mole (kJ/mol).

Identity

Symbol
C
Atomic number
6
Atomic mass
12.011 u
Family
Reactive Nonmetals
Position
group 14, period 2
Block
p-block

Electron configuration

Full
1s2 2s2 2p2
Shorthand
[He] 2s2 2p2
Electrons per shell
2, 4
Outer-shell electrons
4 in shell L

Ionisation energies

I₁
1086.5
I₂
2352.6
I₃
4620.5
I₄
6222.7
I₅
37831
I₆
47277

Energy to remove each electron in turn (kJ/mol). A sharp jump means the next electron comes from an inner shell.

Atomic radii

Calculated (pm)
67
Empirical (pm)
70
Covalent (pm)
75
Van der Waals (pm)
170

Electronegativity and electron affinity

Electronegativity (Pauling)
2.55
Electron affinity (kJ/mol)
121.776

Oxidation states

−4 +4

Charges the element commonly takes in compounds.

Physical properties, abundance and history of carbon

Bulk properties of carbon, how common it is, who discovered it and some of its compounds.

Physical properties

Phase at room conditions
Solid
Melting point
4326.85°C (4600 K)
Density
1.821 g/cm³
Thermal conductivity (W/m·K)
1.59
Specific heat (J/g·K)
0.709
Molar heat capacity (J/mol·K)
8.517

Abundance

Earth's crust (mg/kg)
200
Oceans (mg/L)
28

Discovery

Discovered by
Ancient Egypt
Year
Ancient

Common compounds

  • Methanol CH4O
  • Urea CH4N2O
  • Carbon Tetrachloride CCl4
  • Carbon Disulfide CS2
  • Thiourea CH4N2S
  • Hydrogen Cyanide CHN
  • Formic Acid CH2O2
  • Formaldehyde CH2O

Compounds listed in the PubChem database.

Main isotopes of carbon

Isotopes of carbon share the same 6 protons but differ in neutrons. Natural isotopes come first, then the longest-lived others.

Main isotopes of carbon: mass number, abundance, half-life and decay
Mass numberNatural abundanceHalf-lifeDecay
10–19.301 sβ⁺
11–20.34 minβ⁺
1298.94 %stable–
131.06 %stable–
14–5.7 kyβ⁻
15–2.449 sβ⁻

α = alpha decay, β⁻ = beta-minus, β⁺ = beta-plus, EC = electron capture, SF = spontaneous fission, p / n = proton / neutron emission.

More about carbon