14 Si Silicon 28.085
Metalloid
Silicon 硅
[Ne] 3s² 3p²
- Period 3
- Group 14
- Block p
- Solid
Electron configuration
1s² 2s² 2p⁶ 3s² 3p²
Orbital diagram (valence)
3s ↑↓
3p ↑↑
- Electrons per shell
- 2, 8, 4
- Unpaired electrons
- 2
- Zeff (Slater)
- 4.15
Properties
- Atomic weight
- 28.085
- Electronegativity (Pauling)
- 1.9
- First ionization energy
- 786.5 kJ/mol
- Electron affinity
- 133.6 kJ/mol
- Covalent radius
- 111 pm
- van der Waals radius
- 210 pm
- Melting point
- 1687 K
- Boiling point
- 3538 K
- Density
- 2.33 g/cm³
- Melting / boiling point
- 1413.8 °C / 3264.8 °C
- Common oxidation states
- +4, +2, −4
- Discovered
- 1854
Natural isotopes
| Mass number A | Atomic mass / u | Abundance |
|---|---|---|
| 28Si | 27.976927 | 92.22 % |
| 29Si | 28.976495 | 4.69 % |
| 30Si | 29.973770 | 3.09 % |
Isotope masses: AME2020; abundances: IUPAC/CIAAW representative values.
Successive ionization energies
The big jumps appear where core electrons start to be removed. Ionization energies from the NIST Atomic Spectra Database.
Silicon in the course
The lessons that discuss this element most (ranked by mentions).
- Boron, aluminium, carbon, silicon and the inert pair The main-group elements
- Metals and bands: conductors, semiconductors and colour Crystals and solids
- Oxygen and sulfur The main-group elements
- Extracting metals Transition metals
- Chromatography principles: retention, selectivity and Rf Separations and chromatography
- What makes an acid strong Acids and bases
- Heat capacity of solids and third-law entropy Entropy and free energy
- Batteries: chemistry that stores charge Redox and electrochemistry
Periodic trend
Group 14
Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).