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  2. Helium compounds - Wikipedia

    en.wikipedia.org/wiki/Helium_compounds

    Helium's first ionization energy of 24.57 eV is the highest of any element. [2] Helium has a complete shell of electrons, and in this form the atom does not readily accept any extra electrons nor join with anything to make covalent compounds. The electron affinity is 0.080 eV, which is very close to zero. [2]

  3. Helium - Wikipedia

    en.wikipedia.org/wiki/Helium

    The Rollin film also covers the interior of the larger container; if it were not sealed, the helium II would creep out and escape. [30] Helium II is a superfluid, a quantum mechanical state of matter with strange properties. For example, when it flows through capillaries as thin as 10 to 100 nm it has no measurable viscosity. [28]

  4. Combustibility and flammability - Wikipedia

    en.wikipedia.org/wiki/Combustibility_and...

    A non-combustible material [17] is a substance that does not ignite, burn, support combustion, or release flammable vapors when subject to fire or heat, in the form in which it is used and under conditions anticipated. Any solid substance complying with either of two sets of passing criteria listed in Section 8 of ASTM E 136 when the substance ...

  5. Explainer-What is helium and why is it used in rockets? - AOL

    www.aol.com/news/explainer-helium-why-used...

    Helium is inert - it does not react with other substances or combust - and its atomic number is 2, making it the second lightest element after hydrogen. Rockets need to achieve specific speeds and ...

  6. Superfluidity - Wikipedia

    en.wikipedia.org/wiki/Superfluidity

    In liquid helium-4, the superfluidity occurs at far higher temperatures than it does in helium-3. Each atom of helium-4 is a boson particle, by virtue of its integer spin . A helium-3 atom is a fermion particle; it can form bosons only by pairing with another particle like itself, which occurs at much lower temperatures.

  7. List of alternative nonmetal classes - Wikipedia

    en.wikipedia.org/wiki/List_of_alternative...

    The nonmetallic elements are sometimes instead divided into two to seven alternative classes or sets according to, for example, electronegativity; the relative homogeneity of the halogens; molecular structure; the peculiar nature of hydrogen; the corrosive nature of oxygen and the halogens; their respective groups; and variations thereupon.

  8. List of states of matter - Wikipedia

    en.wikipedia.org/wiki/List_of_states_of_matter

    Quasicrystal: A solid in which the positions of the atoms have long-range order, but this is not in a repeating pattern. Different structural phases of polymorphic materials are considered to be different states of matter in the Landau theory. For an example, see Ice § Phases. Liquid: A mostly non-compressible fluid. Able to conform to the ...

  9. The world is running out of helium. Here's why doctors are ...

    www.aol.com/news/world-running-helium-heres-why...

    A global helium shortage has doctors worried about one of the natural gas’s most essential, and perhaps unexpected, uses: MRIs.. Strange as it sounds, the lighter-than-air element that gives ...