Carbon (C): electron configuration, atomic mass and facts
Carbon (C) is element 6 of the periodic table, a reactive nonmetal in period 2, group 14. Its electron configuration is [He] 2s2 2p2, with electrons arranged in shells 2, 4, and its standard atomic weight is 12.011 u.
💡 Forms more compounds than any other element. Diamond and graphite are both pure carbon.
▶ Watch Carbon’s electrons orbit in the interactive periodic tableCarbon at a glance
| Symbol | C |
|---|---|
| Atomic number | 6 |
| Atomic mass | 12.011 u |
| Category | Reactive nonmetal |
| Group | 14 |
| Period | 2 |
| Block | p-block |
| Electron configuration | 1s2 2s2 2p2 |
| Noble-gas shorthand | [He] 2s2 2p2 |
| Electrons per shell | 2, 4 |
| Outer-shell electrons | 4 |
| Electronegativity (Pauling) | 2.55 |
| State at 20 °C | solid |
Experiments with carbon
🫧 CO₂ and limewater
Marble + acid makes CO₂. Bubble it through limewater: milky, then clear again in excess.
🐍 Black carbon snake
Concentrated sulfuric acid rips water out of sugar, leaving a smoking column of carbon.
🩸 Fe³⁺ thiocyanate test
A drop of thiocyanate turns iron(III) solutions blood red.
🌋 Baking-soda volcano
Vinegar + bicarbonate + washing-up liquid produce a frothy eruption.
Where is Carbon on the periodic table?
Carbon is in period 2, group 14, in the p-block. The period number matches its 2 electron shells, and the block names the subshell its last electrons fill. In the same group, Silicon sits directly below it. Elements in one group have the same number of outer-shell electrons (4 here), which is why they react in similar ways.
How to work out the electron configuration of Carbon
Put 6 electrons into subshells in order of rising energy, filling each before starting the next: 1s² (2), 2s² (4), 2p² (6). In shorthand, [He] stands for the 2 electrons of helium, giving [He] 2s² 2p².
How electronegative is Carbon?
Carbon has a Pauling electronegativity of 2.55, ranking 10 of the 100 elements with a known value (fluorine is highest at 3.98). That is high: it pulls shared electrons strongly towards itself in a bond.
Carbon in the virtual lab
Faradium’s chemistry workbench includes these chemicals that contain carbon: Marble chips, Sodium carbonate, Baking soda, Malachite, Charcoal powder, Sugar (sucrose), Ethanoic acid (vinegar), Sodium hydrogencarbonate, Potassium thiocyanate, Ethanol, Carbon dioxide cylinder. Open the Chemistry Lab to experiment with them.
Frequently asked questions
What is the electron configuration of Carbon?
The electron configuration of Carbon (C) is 1s2 2s2 2p2. In noble-gas shorthand it is written [He] 2s2 2p2.
How many electrons does Carbon have in each shell?
Carbon has 6 electrons arranged in shells as 2, 4. It has 4 electrons in its outer shell.
What is the atomic mass of Carbon?
The standard atomic weight of Carbon is 12.011 u, so one mole of Carbon atoms has a mass of about 12.011 g.
Is Carbon a metal?
No. Carbon is a reactive nonmetal.
Explore nearby elements
More reactive nonmetals: Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur, Selenium. See all elements on the periodic table.