Carbon vs Silicon
Carbon is a non-metal (polyatomic non-metal); Silicon is a metalloid (metalloid).
The differences in plain English
- They sit in the same column, group 14, so they have the same number of outer electrons and react in similar ways; the heavier one, Silicon, is usually the more reactive of the two if they are metals, and the less reactive if they are non-metals.
- Both are solids at room temperature.
- Silicon is denser, about 28 per cent more than Carbon (2.329 against 1.821 g/cm³).
- An atom of Silicon is about 2.3 times heavier than an atom of Carbon (28.09 u against 12.01 u).
- Carbon pulls electrons more strongly in a bond (electronegativity 2.55 against 1.9).
Side by side
| Carbon | Silicon | |
|---|---|---|
| Atomic number | 6 | 14 |
| Symbol | C | Si |
| Family | Polyatomic non-metal | Metalloid |
| Group / period | 14 / 2 | 14 / 3 |
| State at room temperature | Solid | Solid |
| Atomic mass | 12.011 u | 28.085 u |
| Density | 1.821 g/cm³ | 2.329 g/cm³ |
| Melting point | – | 1414 °C |
| Boiling point | – | 3265 °C |
| Electronegativity | 2.55 | 1.9 |
| First ionisation energy | 1086.5 kJ/mol | 786.5 kJ/mol |
| Electron configuration | [He] 2s2 2p2 | [Ne] 3s2 3p2 |
| Discovered by | Ancient Egypt | Jöns Jacob Berzelius |
Carbon
Carbon can be the softest smudge on a page or the hardest natural substance known. It can be jet black or perfectly clear, a conductor of electricity or an insulator. All of this depends on how carbon atoms arrange themselves, because carbon atoms can bond to each other in chains, rings, sheets and three-dimensional frameworks in a way no other element can match.
- Diamond and graphite are both pure carbon, yet one is the hardest natural material and the other is soft enough to write with.
- Graphene, a single layer of carbon atoms, earned Andre Geim and Konstantin Novoselov the Nobel Prize in Physics in 2010. They first peeled it from graphite with sticky tape.
Silicon
Silicon is the element that makes up most of the rock on Earth and most of the technology in your pocket. Combined with oxygen, it forms the silicate minerals of sand, granite, clay and the vast majority of the crust. Refined to a purity of one foreign atom in a billion, it becomes the crystal wafers on which transistors are printed, and the solar cells that turn sunlight into electricity.
- Silicon makes up about 28 per cent of the Earth's crust by mass, second only to oxygen.
- Like water, silicon expands as it freezes, so solid silicon floats on molten silicon.
Colour the bubbles by density or melting point and the difference jumps out.
More comparisons
Data from Periodic-Table-JSON (CC BY-SA); temperatures rounded to the nearest degree. Written by Anthony.