Helium

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Helium
He
In situ availability: trace
Necessity:
Atomic number: 2
Atomic mass: 4.002602
group: 18
period: 1
normal phase: Gas
series: Noble gases
density: 0.1786 g/L
melting point: 0.95K,
-272.2°C,
-458.0°F
boiling point: 4.22K,
-268.93°C,
-452.07°F
N/AN/AN/A
H ← He → Li
FNeN/A
Atomic radius (pm): 31 pm
Bohr radius (pm):
Covalent radius (pm): 32
Van der Waals radius (pm): 140
ionic radius (pm): -
1st ion potential (eV): 24.59
Electron Configuration
1s2
Electrons Per Shell
2
Electronegativity:
Electron Affinity: Unstable anion
Oxidation states: -
Magnetism:
Crystal structure: Hexagonal or body centered cubic

Helium is a component of the solar wind, and hence is one of the volatiles found (in parts per million level) in Lunar regolith. It is a Noble gas in group 18 and is the second element in the Periodic Table of the Elements. This element has two stable isotopes: 3 and 4.

The most common isotope, Helium-4, has a nucleus of two protons and two neutrons, and two electrons. The less common isotope Helium-3 has two protons and one neutron.

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Applications

An He-Ne laser
  • Medical Lung Imaging
According to Wikipedia:
http://en.wikipedia.org/wiki/Helium_3
Details on this experimental application of He3: http://cerncourier.com/main/article/41/8/14
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