Helium
2
He
Groep
18
Periode
1
Blok
s
Protrone
Elektrone
Neutrone
2
2
2
Algemene Eienskappe
Atoom Nommer
2
Atoommassa
4,002602
Massa Nommer
4
Kategorie
Edelgasse
Kleur
Kleurloos
Radioaktief
Nee
From the Greek word helios, the sun
Kristalstruktuur
Gesiggesentreerde kubieke
Geskiendenis
French astronomer Jules Janssen obtained the first evidence of helium during the solar eclipse of 1868.
Norman Lockyer and Edward Frankland suggested the name helium for the new element.
In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite.
It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet.
Norman Lockyer and Edward Frankland suggested the name helium for the new element.
In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite.
It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet.
Elektrone per skil
2
Elektronkonfigurasie
1s2
Unlike any other element, helium will remain liquid down to absolute zero at normal pressures
Fisiese Eienskappe
Fase
Gas
Digtheid
0,0001785 g/cm3
Smeltpunt
0,95 K | -272,2 °C | -457,96 °F
Kookpunt
4,22 K | -268,93 °C | -452,07 °F
Heat of Fusion
0,02 kJ/mol
Heat of Vaporization
0,083 kJ/mol
Spesifieke Hitte Kapasiteit
5,193 J/g·K
Oorvloed in die aardkors
5,5×10-7%
Oorvloed in die heelal
23%
CAS Nommer
7440-59-7
PubChem CID Nommer
23987
Atomiese Eienskappe
Atoom radius
31 pm
Kovalente Radius
28 pm
Elektronegatiewiteit
-
Ionisasie potensiaal
24,5874 eV
Atoom volume
27,2 cm3/mol
Termiese geleidingsvermoë
0,00152 W/cm·K
Oksidasiestate
0
Toepassings
Helium is used as a protective gas in growing silicon and germanium crystals, in titanium and zirconium production, and in gas chromatography.
Helium at low temperatures is used in cryogenics.
Helium is used for filling balloons and for pressurizing liquid fuel rockets.
Helium is used as a shielding gas in arc welding processes.
Helium at low temperatures is used in cryogenics.
Helium is used for filling balloons and for pressurizing liquid fuel rockets.
Helium is used as a shielding gas in arc welding processes.
Helium is not known to be toxic
Isotope
Stabiele Isotope
3He, 4HeOnstabiele Isotope
5He, 6He, 7He, 8He, 9He, 10He