Silicon (Si)
Silicon is element 14, a metalloid in period 3, group 14 of the periodic table. At room temperature it is a solid.
Electron configuration [Ne] 3s2 3p2
Electrons per shell 2, 8, 4
Silicon data
| Atomic number | 14 |
|---|---|
| Symbol | Si |
| Atomic mass | 28.085 u |
| Category | Metalloid |
| Group | 14 |
| Period | 3 |
| Block | p |
| State at 25 °C | solid |
| Melting point | 1687 K (1413.9 °C) |
| Boiling point | 3173 K (2899.9 °C) |
| Density | 2.33 g/cm³ |
| Electronegativity (Pauling) | 1.9 |
| Atomic radius | 111 pm |
| 1st ionization energy | 787 kJ/mol |
| Electron affinity | -134 kJ/mol |
| Oxidation states | -4, -3, -2, -1, +1, +2, +3, +4 |
| Common ion charge | 4+ |
| Discovered | 1854 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through silicon’s configuration and its ions →
Where silicon sits
Silicon belongs to the metalloids. Its Pauling electronegativity of 1.9 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Silicon FAQ
What is the electron configuration of silicon?
Silicon (Z = 14) has the configuration 1s2 2s2 2p6 3s2 3p2. In noble-gas shorthand that is [Ne] 3s2 3p2.
How many valence electrons does silicon have?
4 (outer shell (n = 3)).
What is the atomic mass of silicon?
The standard atomic weight of silicon is 28.085 u, so one mole weighs 28.085 g.
Is silicon a metal?
Silicon is a metalloid: it has properties between metals and nonmetals.
What is the charge of a silicon ion?
Silicon most commonly forms Si4+.