Helium
Helium
Hydrogen Helium Lithium Beryllium Boron Blank Helium Neon Argon Krypton Xenon Radon Ununoctium
Name:
Helium
Symbol:
He
Atomic Number:
2
Atomic Weight:
4.0026(2)
Density:
0.000178 g/cc
Melting Point:
-272.2 C
Boiling Point:
-268.934 C
Electron Configuration:
1s2
Chemical Group:
Noble Gases
Detailed Technical Data

The data on this page is more precise and in some cases more up-to-date than the data engraved on the wooden tiles. But as always, never believe one source if the number really matters. Density, melting point and boiling point data is particularly variable and uncertain.

Atomic weight data for stable elements from IUPAC 1999 Official Publication. (Uncertainty in parentheses.)

Special notes for this element from IUPAC publication:
Geological specimens are known in which the element has an isotopic composition outside the limits for normal material. The difference between the atomic weight of the element in such specimens and that given in the Table may exceed the stated uncertainty.

Range in isotopic composition of normal terrestrial material prevents a more precise Ar(E) being given; the tabulated Ar(E) value should be applicable to any normal material.