Silicon (Si)
Silicon is element 14, a metalloid in group 14, period 3. A neutral atom has 14 protons, 14 neutrons and 14 electrons, 4 of them valence electrons.
Metalloid- Atomic number
- 14
- Atomic mass
- 28.085 u
- Valence electrons
- 4
- Protons · neutrons
- 14 · 14
- Electrons per shell
- 2, 8, 4
- At room temperature
- solid
Bohr model of silicon
The Bohr model draws silicon as a nucleus of 14 protons and 14 neutrons, with its 14 electrons on 3 circular shells: 2 in shell 1, 8 in shell 2, 4 in shell 3. Press Build the atom to watch the shells fill from the inside out. The outer ring (the M shell) is dashed: the electrons there are the ones that take part in chemistry.
Real electrons don't travel in neat circles. They live in fuzzy orbitals, shown below, but the Bohr picture is the quickest way to count shells and valence electrons.
Electron configuration of silicon
1s² 2s² 2p⁶ 3s² 3p²
Short form (noble gas notation): [Ne] 3s² 3p². The [Ne] stands for the electrons of neon, the noble gas before it.
How many valence electrons does silicon have?
Silicon has 4 valence electrons.
Silicon is in group 14, and for groups 13–18 you subtract 10 from the group number: 14 − 10 = 4. It tends to share electrons in covalent bonds.
Protons, neutrons and electrons
| Protons | 14 | equal to the atomic number |
|---|---|---|
| Electrons | 14 | equal to the protons in a neutral atom |
| Neutrons | 14 | mass number 28 − 14 protons |
Atoms of the same element can have different numbers of neutrons (isotopes). The count above uses the rounded atomic mass, the way it's taught in class.
Silicon properties
| Symbol | Si |
|---|---|
| Category | Metalloid |
| Group · period · block | 14 · 3 · p |
| Atomic mass | 28.085 u |
| State at 25 °C | solid |
| Melting point | 1,687 K (1,410 °C, 2,580 °F) |
| Boiling point | 3,538 K (3,260 °C, 5,910 °F) |
| Density | 2.3296 g/cm³ |
| Electronegativity (Pauling) | 1.9 |
| Atomic radius | 210 pm |
| First ionization energy | 8.152 eV |
| Electron affinity | 1.385 eV |
| Oxidation states | +4, +2, −4 |
| Common ion charge | +4, +2 |
| Discovered | 1854 by Jöns Jacob Berzelius |
Where silicon sits on the periodic table
Group 14: Carbon, Germanium, Tin, Lead, Flerovium.
Questions about silicon
How many valence electrons does silicon have?
Silicon has 4 valence electrons.
How many protons, neutrons and electrons does silicon have?
A neutral silicon atom has 14 protons and 14 electrons. Its most common form has about 14 neutrons (mass number 28 − 14 protons).
What is the electron configuration of silicon?
1s² 2s² 2p⁶ 3s² 3p², written in short form as [Ne] 3s² 3p².
What does the Bohr model of silicon look like?
A nucleus of 14 protons and 14 neutrons, circled by 3 electron shells holding 2, 8, 4 electrons.
What is the atomic number of silicon?
14. The atomic number is the number of protons in the nucleus, and it is what makes an atom silicon.