Hélium
2
He
Skupina
18
Perióda
1
Orbitál
s
Protóny
Elektróny
Neutróny
2
2
2
Hlavné vlastnosti
Protónové číslo
2
Atómová hmotnosť
4,002602
Hmotnostné číslo
4
Kategória
Vzácne plyny
Farba
Bezfarebný
Rádioaktívny
Nie
Z Gréckeho slova helios (slnko)
Kryštálová sústava
Tvárovo-centrovaný kockový
História
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.
Elektróny v obale
2
Elektrónová konfigurácia
1s2
Unlike any other element, helium will remain liquid down to absolute zero at normal pressures
Fyzikálne vlastnosti
Skupenstvo
Plyny
Hustota
0,0001785 g/cm3
Teplota topenia
0,95 K | -272,2 °C | -457,96 °F
Teplota varu
4,22 K | -268,93 °C | -452,07 °F
Skupenské teplo topenia
0,02 kJ/mol
Skupenské teplo varu
0,083 kJ/mol
Tepelná kapacita
5,193 J/g·K
Množstvo v zemskej kôre
5,5×10-7%
Množstvo vo vesmíre
23%
![Vial](https://periodic-table.io/images/elements/He.jpg)
Registračné číslo CAS
7440-59-7
PubChem CID číslo
23987
Atómové vlastnosti
Atómový polomer
31 pm
Kovalentný polomer
28 pm
Elektronegativita
-
Ionizačný potenciál
24,5874 eV
Atómový objem
27,2 cm3/mol
Tepelná vodivosť
0,00152 W/cm·K
Oxidačné stavy
0
Aplikácie
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
Izotopy
Stabilné izotopy
3He, 4HeNestabilné izotopy
5He, 6He, 7He, 8He, 9He, 10He