Helium

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/A ← N/A → N/A
H ← He → N/A
F ← Ne → N/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.

The paroagn of understanding these issues is right here!