FANDOM


Helium-anim

A helium atom

Helium
Helium
2He
-

He

Ne
HydrogenHeliumLithium
Appearance
General properties
Name, symbol, number Helium, He, 2
Element category noble gases
Group, period, block 18, 2, s
Standard atomic weight 4.002602
Electron configuration 1s2
[1]
2
[1]
Electron shell 002 Helium - no label.svg
History
Discovery William Ramsay
Physical properties
Phase gas
Density (near r.t. (0 °C, 101.325 kPa)

0.1786 g/L

Melting point 0.95 K
Boiling point 4.22 K
Critical point 154.59 K
Heat of fusion 0.0138 kJ·mol-1
Heat of vaporization 0.0829 kJ·mol-1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 3 4
Atomic properties
Ionization energies 2372.3 KJ/mol
Atomic radius 31 pm
Covalent radius 32 pm
Van der Waals radius 140 pm
Crystal structure Hexagonal or bcc
Thermal conductivity (300 K) 151.3 mW/(m/K)
CAS registry number 7440-59-7
vter

Helium is a gas with an atomic number 2. It Helijng the Rollin film on any surface. The element's name comes from the Greek word 'ήλιος (helios)' which means sun as sun performs hydrogen fusion as fuel producing helium.

It is a gas element.

Isotopes Edit

Diproton

Helium-3

Helium-4


Cite error: <ref> tags exist, but no <references/> tag was found

Ad blocker interference detected!


Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.