Helium

Analytical testing dots

Helium (He) is a colorless, odorless, tasteless, non-toxic, inert monatomic chemical element that heads the noble gas series in the periodic table and whose atomic number is 2. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions. Extreme conditions are also needed to create the small handful of helium compounds, which are all unstable at standard temperature and pressure. In its most common form, helium-4, it has two neutrons in its nucleus, while a second, rarer, stable isotope called helium-3 contains just one neutron. The behavior of liquid helium-4's two fluid phases, helium I and helium II, is important to researchers studying quantum mechanics (in particular the phenomenon of superfluidity) and to those looking at the effects that temperatures near absolute zero have on matter (such as superconductivity).

 

General
Atomic number:   2
Symbol:   He
Atomic weight:   4.0026
Boiling Point (C):   -268.9
Melting Point (C):   -269.7
Density:   .126
heatVapor:   0.02
heatFusion:   0.005
Electrical Conductivity:   --
Thermal Conductivity:   0.0003
Specific Heat Capacity:   1.25

 

View the Periodic Table...

View the List of Elements...

Analytical testing dots

Content from Wikipedia for educational use and displayed with permission under the GFDL.
Please report any inaccuracies to the Webmaster.