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Helium (He) - Properties


Atomic mass, symbol and atomic number

helium is a naturally occurring element with the element symbol He and atomic number 2. In the periodic table it stands with an atomic mass of 4.002 u in the 8th main group. The chemical element discovered by William Ramsay in 1895 is not radioactive and is in a gaseous state at room temperature.

Profile: Helium

General
Chemical element:helium
Symbol:He
Atomic number:2
Group:18
Period:1
Block:s block
Series:noble gases
Appearance:colorless
explorers:William Ramsay
Year of discovery:1895
Atomic properties
Atomic mass:4,002 u
Atomic radius:???
Covalent radius:28 pm
Van der Waals radius:140 pm
Electron configuration:1s2
ionization:2372.3 kJ / mol
Physical Properties
Physical state:gaseous
Density:???
Crystal structure:/
Magnetism:diamagnetic
molar volume:21,00 · 10-6 m3/ mol
Mohs hardness:/
Melting point:-272 ° C
Boiling point:-269 ° C
Heat of fusion:0.02 kJ / mol
Heat of vaporization:0.084 kJ / mol
Thermal conductivity:0.151 W
Chemical properties
electronegativity:?

Did you know that ...

  • Helium is the second most common element in space?
  • Helium is suitable as a balloon gas because it does not explode compared to other gases?
  • Helium causes the voice to change in the short term?
  • Helium does not form any compounds with other elements and therefore only occurs as elemental helium?
  • the name helium can be derived from the Greek and means sun?