Helium

Tuesday, February 26, 2013

Helium is an inert, very light, gaseous element, present in the Sun's atmosphere, some minerals, natural gas, etc. It also occurs as a radioactive decomposition product and is used as substitute for flammable gases in dirigible balloons. Symbol He; atomic number 2; atomic weight 4.0026; density 0.1785 at 0ÂșC.