Silicon

Symbol	Si
Atomic number	14
Group	14 (Carbon group)
Period	3
Block	p
Classification	Metalloid

Appearance	Crystalline, reflective with bluish-tinged faces
Color	Gray

Number of protons	14 p+
Number of neutrons	14 n0
Number of electrons	14 e-

From Wikipedia, the free encyclopediaSilicon 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.

Phase at STP	Solid
Density	2.329 g/cm3
Atomic weight	28.084 u

Melting point	1687 K 1413.85 °C 2576.93 °F
Boiling point	3538 K 3264.85 °C 5908.73 °F
Heat of vaporization	359 kJ/mol

Electronegativity (Pauling Scale)	1.9
Electron affinity	134.068 kJ/mol
Oxidation states	−4, −3, −2, −1, 0, +1, +2, +3, +4 (an amphoteric oxide)
Ionization energies	786.5 kJ/mol 1577.1 kJ/mol 3231.6 kJ/mol 4355.5 kJ/mol 16091 kJ/mol 19805 kJ/mol 23780 kJ/mol 29287 kJ/mol 33878 kJ/mol 38726 kJ/mol 45962 kJ/mol 50502 kJ/mol 235196 kJ/mol 257923 kJ/mol

Electron configuration Shorthand configuration	[Ne] 3s2 3p2
Electron configuration Full configuration	1s2 2s2 2p6 3s2 3p2
Electron configuration chart	1s2 2s2 2p6 3s2 3p2
Electrons per shell	2, 8, 4
Valence electrons	4
Valency electrons	4
Bohr model	Figure: Shell diagram of Silicon (Si) atom.
Orbital Diagram	1s 2s 2p 3s 3p

Prediction	Antoine Lavoisier (1787)
Discovery and first isolation	Jöns Jacob Berzelius (1823)
Named by	Thomas Thomson (1817)
Discovery of silicon In 1787, Antoine Lavoisier suspected that silica might be an oxide of a fundamental chemical element. After an attempt to isolate silicon in 1808, Sir Humphry Davy proposed the name "silicium" for silicon. Gay-Lussac and Thénard are thought to have prepared impure amorphous silicon in 1811, through the heating of recently isolated potassium metal with silicon tetrafluoride, but they did not purify and characterize the product, nor identify it as a new element. Silicon was given its present name in 1817 by Scottish chemist Thomas Thomson. He retained part of Davy's name but added "-on" because he believed that silicon was a nonmetal similar to boron and carbon. In 1824, Jöns Jacob Berzelius prepared amorphous silicon using approximately the same method as Gay-Lussac (reducing potassium fluorosilicate with molten potassium metal), but purifying the product to a brown powder by repeatedly washing it. As a result, he is usually given credit for the element's discovery.

Original word	silex
Language of origin	Latin
Name source	Mineral
Meaning	“Flint”
Naming The name is derived from the Latin word silex or silicis, meaning flint or hard stone.

CAS Number	7440-21-3
ChemSpider ID	4574465
EC number	231-130-8
PubChem CID Number	5461123