Silicon (Si) – element 14
Silicon is a chemical element with the symbol Si and atomic number 14. It is a metalloid in group 14, period 3 of the periodic table (p-block), and is a solid at room temperature.
Silicon (Si) has atomic number 14, atomic mass 28.085 u and electron configuration [Ne] 3s2 3p2.
Silicon facts
| Symbol | Si |
|---|---|
| Atomic number | 14 |
| Atomic mass | 28.085 u (g/mol) |
| Category | metalloid |
| Group | group 14 |
| Period | 3 |
| Block | p-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p2 |
| Noble-gas notation | [Ne] 3s2 3p2 |
| Electrons per shell | 2, 8, 4 |
| Valence electrons | 4 |
Bohr model and shells
Silicon has 14 electrons in 3 shells: 2, 8, 4. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 1687 K (1413.8 °C) |
|---|---|
| Boiling point | 3538 K (3264.8 °C) |
| Density | 2.329 g/cm³ |
| Electronegativity (Pauling) | 1.9 |
| Electron affinity | 134.068 kJ/mol |
| Ionization energies | 786.5, 1577.1, 3231.6 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 19.789 J/(mol·K) |
| Discovered by | Jöns Jacob Berzelius |
Use the atomic mass in the molar mass calculator for any formula containing Si.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of silicon?
The atomic mass of silicon is 28.085 u, so one mole of silicon atoms weighs 28.085 g.
What is the electron configuration of silicon?
Silicon has 14 electrons: 1s² 2s² 2p⁶ 3s² 3p², or [Ne] 3s² 3p² in noble-gas notation. Electrons per shell: 2, 8, 4.
How many valence electrons does silicon have?
Silicon has 4 valence electrons (group 14).
Is silicon a metal?
Silicon is a metalloid: it has properties between metals and nonmetals.
Where is silicon on the periodic table?
Silicon is in group 14, period 3, in the p-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.