Seleni
34
Se
Grup
16
Període
4
Bloc
p
Protons
Electrons
Neutrons
34
34
45
Propietats Generals
Nombre atòmic
34
Massa atòmica
78,96
Nombre de massa
79
Categoria
Altres no metalls
Color
Gris
Radioactiu
No
From the Greek word Selene, moon
Estructura cristal·lina
Monoclinica simple
Història
Selenium was first observed in about the year 1300 by the alchemist Arnold of Villanova.
Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn who noted the similarity of the new element to the previously-known tellurium.
In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light.
Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn who noted the similarity of the new element to the previously-known tellurium.
In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light.
Electrons per capa
2, 8, 18, 6
Configuració electrònica
[Ar] 3d10 4s2 4p4
Selenium deficiency in animals can lead to slow growth
Propietats Físiques
Fase
Sòlid
Densitat
4,809 g/cm3
Punt de fusió
494,15 K | 221 °C | 429,8 °F
Punt d'ebullició
958,15 K | 685 °C | 1265 °F
Entalpia de fusió
5,4 kJ/mol
Entalpia de vaporització
26 kJ/mol
Capacitat tèrmica específica
0,321 J/g·K
Abundància a l'escorça terrestre
5×10-6%
Abundància a l'univers
3×10-6%
Número CAS
7782-49-2
Número CID de PubChem
6326970
Propietats Atòmiques
Radi atòmic
120 pm
Radi covalent
120 pm
Electronegativitat
2,55 (Escala de Pauling)
Potencial d'ionització
9,7524 eV
Volum atòmic
16,45 cm3/mol
Conductivitat tèrmica
0,0204 W/cm·K
Estats d'oxidació
-2, 2, 4, 6
Aplicacions
Selenium is used in the glass industry to decolorize glass and to make red-colored glasses and enamels.
It is used as a catalyst in many chemical reactions.
It is also used as a photographic toner, and as an additive to stainless steel.
Selenium sulfide is used in anti-dandruff shampoos.
It is used as a catalyst in many chemical reactions.
It is also used as a photographic toner, and as an additive to stainless steel.
Selenium sulfide is used in anti-dandruff shampoos.
Many of selenium's compounds, such as selenates and selenites, are highly toxic
Isòtops
Isòtops estables
74Se, 76Se, 77Se, 78Se, 80SeIsòtops inestables
65Se, 66Se, 67Se, 68Se, 69Se, 70Se, 71Se, 72Se, 73Se, 75Se, 79Se, 81Se, 82Se, 83Se, 84Se, 85Se, 86Se, 87Se, 88Se, 89Se, 90Se, 91Se, 92Se, 93Se, 94Se