Silicon Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Silicon is a chemical element with symbol Si and atomic number 14. It is a tetravalent Metalloid, more reactive than germanium, the Metalloid directly below it in the table. Controversy about silicon's character dates to its discovery.
It belongs to group 14 of the periodic table having trivial name tetrels, crystallogens. You can also download Printable Periodic Table of Elements Flashcards for Silicon in a PDF format.
Silicon Facts
Read key information and facts about element Silicon
| Name | Silicon |
| Atomic Number | 14 |
| Atomic Symbol | Si |
| Atomic Weight | 28.0855 |
| Phase | Solid |
| Color | Gray |
| Appearance | crystalline, reflective with bluish-tinged faces |
| Classification | Metalloid |
| Natural Occurance | Primordial |
| Group in Periodic Table | 14 |
| Group Name | carbon family |
| Period in Periodic Table | period 3 |
| Block in Periodic Table | p-block |
| Electronic Configuration | [Ne] 3s2 3p2 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 4 |
| Melting Point | 1687 K |
| Boiling Point | 3173 K |
| CAS Number | CAS7440-21-3 |
How to Locate Silicon on Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 14 to find Silicon on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Silicon on periodic table look for cross section of group 14 and period 3 in the modern periodic table.
Silicon History
The element Silicon was discovered by J. Berzelius in year 1823 in Sweden. Silicon was first isolated by J. Berzelius in 1823. Silicon derived its name from the Latin silex, 'flint' (originally silicium).
| Discovered By | J. Berzelius |
| Discovery Date | 1823 in Sweden |
| First Isolation | 1823 |
| Isolated by | J. Berzelius |
Humphry Davy thought in 1800 that silica was a compound, not an element, and in 1808 suggested the present name. In 1811 Louis-Joseph Gay-Lussac and Louis-Jacques Thénard probably prepared impure silicon, but Berzelius is credited with the discovery for obtaining the pure element in 1823.
Silicon Uses
Silicon is used majorly in the semiconductor industry in solid-state electronics. To use it there, the silicon has to be doped with boron, gallium, phosphorus, or arsenic.
Silicon Presence: Abundance in Nature and Around Us
The table below shows the abundance of Silicon in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
| ppb by weight (1ppb =10^-7 %) | ppb by atoms (1ppb =10^-7 %) | |
|---|---|---|
| Abundance in Universe | 700000 | 30000 |
| Abundance in Sun | 900000 | 40000 |
| Abundance in Meteorites | 140000000 | 100000000 |
| Abundance in Earth's Crust | 270000000 | 200000000 |
| Abundance in Oceans | 1000 | 220 |
| Abundance in Humans | 260000 | 58000 |
Crystal Structure of Silicon
The solid state structure of Silicon is Tetrahedral Packing.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
Unit Cell Parameters
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
| a | b | c |
|---|---|---|
| 543.09 pm | 543.09 pm | 543.09 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
| alpha | beta | gamma |
|---|---|---|
| π/2 | π/2 | π/2 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
| Space Group Name | Fd_ 3m |
| Space Group Number | 227 |
| Crystal Structure | Tetrahedral Packing |
| Number of atoms per unit cell |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Silicon Atomic and Orbital Properties
Silicon atoms have 14 electrons and the electronic shell structure is [2, 8, 4] with Atomic Term Symbol (Quantum Numbers) 3P0.
| Atomic Number | 14 |
| Number of Electrons (with no charge) | 14 |
| Number of Protons | 14 |
| Mass Number | 28 |
| Number of Neutrons | 14 |
| Shell structure (Electrons per energy level) | 2, 8, 4 |
| Electron Configuration | [Ne] 3s2 3p2 |
| Valence Electrons | 3s2 3p2 |
| Valence (Valency) | 4 |
| Main Oxidation States | -4, 4 |
| Oxidation States | -4, -3, -2, -1, 0, 1, 2, 3, 4 |
| Atomic Term Symbol (Quantum Numbers) | 3P0 |
Bohr Atomic Model of Silicon - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Silicon - neutral Silicon atom
Abbreviated electronic configuration of Silicon
The ground state abbreviated electronic configuration of Neutral Silicon atom is [Ne] 3s2 3p2. The portion of Silicon configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Ne]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 3s2 3p2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Silicon
Complete ground state electronic configuration for the Silicon atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.
As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
Atomic Structure of Silicon
Silicon atomic radius is 111 pm, while it's covalent radius is 111 pm.
| Atomic Radius Calculated | 111 pm(1.11 Å) |
| Atomic Radius Empirical | 110 pm (1.1 Å) |
| Atomic Volume | 12.054 cm3/mol |
| Covalent Radius | 111 pm (1.11 Å) |
| Van der Waals Radius | 210 pm |
| Neutron Cross Section | 171 |
| Neutron Mass Absorption | 0.0002 |
Spectral Lines of Silicon - Atomic Spectrum of Silicon
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.
Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.
Emission spectrum of Silicon
Absorption spectrum of Silicon
Silicon Chemical Properties: Silicon Ionization Energies and electron affinity
The electron affinity of Silicon is 133.6 kJ/mol.
| Valence | 4 |
| Electronegativity | 1.9 |
| ElectronAffinity | 133.6 kJ/mol |
Ionization Energy of Silicon
Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).
Refer to table below for Ionization energies of Silicon
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 786.5 |
| 2nd | 1577.1 |
| 3rd | 3231.6 |
| 4th | 4355.5 |
| 5th | 16091 |
| 6th | 19805 |
| 7th | 23780 |
| 8th | 29287 |
| 9th | 33878 |
| 10th | 38726 |
| 11th | 45962 |
| 12th | 50502 |
| 13th | 235196 |
| 14th | 257923 |
Silicon Physical Properties
Refer to below table for Silicon Physical Properties
| Density | 2.33 g/cm3(when liquid at m.p density is $2.57 g/cm3) |
| Molar Volume | 12.054 cm3/mol |
Elastic Properties
| Young Modulus | 47 |
| Shear Modulus | - |
| Bulk Modulus | 100 GPa |
| Poisson Ratio | - |
Hardness of Silicon - Tests to Measure of Hardness of Element
| Mohs Hardness | 6.5 MPa |
| Vickers Hardness | - |
| Brinell Hardness | - |
Silicon Electrical Properties
Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).
Silicon is a Semiconductor. Refer to table below for the Electrical properties of Silicon
| Electrical conductors | Semiconductor |
| Electrical Conductivity | 1000 S/m |
| Resistivity | 0.001 m Ω |
| Superconducting Point | - |
Silicon Heat and Conduction Properties
| Thermal Conductivity | 150 W/(m K) |
| Thermal Expansion | 0.0000026 /K |
Silicon Magnetic Properties
| Magnetic Type | Diamagnetic |
| Curie Point | - |
| Mass Magnetic Susceptibility | -1.6e-9 m3/kg |
| Molar Magnetic Susceptibility | -4.49e-11 m3/mol |
| Volume Magnetic Susceptibility | -0.00000373 |
Optical Properties of Silicon
| Refractive Index | - |
Acoustic Properties of Silicon
| Speed of Sound | 2200 m/s |
Silicon Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Silicon
| Melting Point | 1687 K(1413.85 °C, 2576.930 °F) |
| Boiling Point | 3173 K(2899.85 °C, 5251.730 °F) |
| Critical Temperature | - |
| Superconducting Point | - |
Enthalpies of Silicon
| Heat of Fusion | 50.2 kJ/mol |
| Heat of Vaporization | 359 kJ/mol |
| Heat of Combustion | -9055 J/(kg K) |
Silicon Isotopes - Nuclear Properties of Silicon
Silicon has 23 isotopes, with between 22 and 44 nucleons. Silicon has 3 stable naturally occuring isotopes.
Isotopes of Silicon - Naturally occurring stable Isotopes: 28Si, 29Si, 30Si.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 22Si | 14 | 8 | 22 | Synthetic | ||
| 23Si | 14 | 9 | 23 | Synthetic | ||
| 24Si | 14 | 10 | 24 | Synthetic | ||
| 25Si | 14 | 11 | 25 | Synthetic | ||
| 26Si | 14 | 12 | 26 | Synthetic | ||
| 27Si | 14 | 13 | 27 | Synthetic | ||
| 28Si | 14 | 14 | 28 | 92.2297% | Stable | |
| 29Si | 14 | 15 | 29 | 4.6832% | Stable | N/A |
| 30Si | 14 | 16 | 30 | 3.0872% | Stable | N/A |
| 31Si | 14 | 17 | 31 | Synthetic | ||
| 32Si | 14 | 18 | 32 | Synthetic | ||
| 33Si | 14 | 19 | 33 | Synthetic | ||
| 34Si | 14 | 20 | 34 | Synthetic | ||
| 35Si | 14 | 21 | 35 | Synthetic | ||
| 36Si | 14 | 22 | 36 | Synthetic | ||
| 37Si | 14 | 23 | 37 | Synthetic | ||
| 38Si | 14 | 24 | 38 | Synthetic | ||
| 39Si | 14 | 25 | 39 | Synthetic | ||
| 40Si | 14 | 26 | 40 | Synthetic | ||
| 41Si | 14 | 27 | 41 | Synthetic | ||
| 42Si | 14 | 28 | 42 | Synthetic | ||
| 43Si | 14 | 29 | 43 | Synthetic | ||
| 44Si | 14 | 30 | 44 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.
| DOT Numbers | 1346 |
| DOT Hazard Class | 4.1 |
NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.
The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.
| NFPA Fire Rating | 0 | Will not burn |
| NFPA Health Rating | 1 | Flash Points Above 93.3°C (200°F) |
| NFPA Reactivity Rating | 0 | Will not burn |
| NFPA Hazards |
| Autoignition Point | 150 °C |
| Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-21-3 |
| RTECS Number | RTECSVW0400000 |
| CID Number | CID5461123 |
| Gmelin Number | - |
| NSC Number | - |
Compare Silicon with other elements
Compare Silicon with Group 14, Period 3 and Metalloid elements of the periodic table.
Compare Silicon with all Group 14 elements
Compare Silicon with all Period 3 elements
Compare Silicon with all Metalloid elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Silicon