Helium
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Helium is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling
Helium discharge tube
Spectral lines of helium
Sir William Ramsay, the discoverer of terrestrial helium
The cleveite sample from which Ramsay first purified helium
Lithium
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Lithium is a chemical element; it has symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid element.
Helium
…when placed in an electric field Standard atomic weight Ar°(He) 4.002602±0.000002 4.0026±0.0001 (abridged) Helium in the periodic table Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium…
Lithium ingots with a thin layer of black nitride tarnish
Lithium floating in oil
Nova Centauri 2013, a stellar nova from which lithium was detected
Johan August Arfwedson is credited with the discovery of lithium in 1817.