Veyer o codigo fuent de «Helio»

{{Grafía EFA}}
{{Ficha d'elemento quimico
|name=Helio
|number=2
|symbol=He
|left=[[Hidrocheno]]
|right=[[Litio]]
|above=-
|below=[[neón|Ne]]
|series=Gas noble
|series comment=
|group=18
|period=1
|block=s
|series color=
|phase color=
|appearance=Incoloro
|image name=
|image name comment=
|image name 2=
|image name 2 comment=
|atomic mass=4.002602
|atomic mass 2=2
|atomic mass comment=
|electron configuration=1s<sup>2</sup>
|electrons per shell=2
|color=
|phase=gas
|phase comment=
|density gplstp=0.1786
|density gpcm3nrt=
|density gpcm3mp=
|melting point K=(at 2.5 MPa) 0.95
|melting point C=−272.20
|melting point F=−457.96
|boiling point K=4.22
|boiling point C=−268.93
|boiling point F=−452.07
|critical point K=5.19
|critical point MPa=0.227
|heat fusion=0.0138
|heat vaporization=0.0829
|heat capacity=20.786
|vapor pressure 1=&nbsp;
|vapor pressure 10=&nbsp;
|vapor pressure 100=1.23
|vapor pressure 1 k=1.67
|vapor pressure 10 k=2.48
|vapor pressure 100 k=4.21
|vapor pressure comment=
|crystal structure=Hexagonal
|oxidation states=
|oxidation states comment=
|electronegativity= 
|number of ionization energies=2
|1st ionization energy=2372.3
|2nd ionization energy=5250.5
|3rd ionization energy=
|atomic radius=
|atomic radius calculated=[[1 E-11 m|31]]
|covalent radius=[[1 E-11 m|32]]
|Van der Waals radius=[[1 E-10 m|140]]
|magnetic ordering=
|electrical resistivity=
|electrical resistivity at 0=
|electrical resistivity at 20=
|thermal conductivity=0.1513&nbsp;
|thermal conductivity 2=
|thermal diffusivity=
|thermal expansion=
|thermal expansion at 25=
|speed of sound rod at 20=
|speed of sound rod at r.t.=
|Young's modulus=
|Shear modulus=
|Bulk modulus=
|Poisson ratio=
|Mohs hardness=
|Vickers hardness=
|Brinell hardness=
|CAS number=7440-59-7
|isotopes=
{{Ficha d'elemento quimico/Isotopo estable | mn=3 | sym=He | na=0.000137%| n=1 | link=Helium-3 }}
{{Ficha d'elemento quimico/Isotopo estable | mn=4 | sym=He | na=99.999863%| n=2 | link=Helium-4 }}
|isotopes comment=
}}
L''''helio''' ye un [[elemento quimico]] de [[numero atomico]] 2 y simbolo '''He'''. Encara que a suya [[confeguración eletronica]] ye 1s<sup>2</sup>, l'helio no fegura en o grupo 2 d'a [[tabla periodica]], chunto a o [[hidrocheno]] en o [[Elementos d'o bloque s|bloque s]], sino que se troba en o grupo 18 d'o [[Elementos d'o bloque p|bloque p]], ya que en tener o [[nivel d'enerchía]] completo, presenta as propiedaz d'un [[gas noble]], ye decir, ye inerte (no reacciona) y igual que istos, ye un gas monoatomico incolor y inodoro.
[[Imachen:HeNe Laser Build.webm|miniaturadeimagen|Rayo láser de helio]]
L'helio tien o menor punto d'evaporación de toz os elementos quimicos, y nomás puet estar solidificato baixo presions muit grans. Dimpués d'o hidrocheno, ye o segundo elemento quimico en abundancia en l'[[universo]], creyato en o proceso de [[fusión nucleyar]] en as [[estrela]]s. En a [[Tierra]], nomás se troba en cantidaz significativas en o [[gas natural]], trobando-se en l'[[atmosfera terrestre|atmosfera]] trazas debitas a la [[desintegración]] de bels elementos.

{{Control d'autoridaz}}

[[Categoría:Elementos quimicos]]
[[Categoría:Gases nobles]]