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Helium is a commonly used carrier gas for gas chromatography. The age of rocks and minerals that contain uranium and thorium can be estimated by measuring the level of helium with a process known as helium dating. [28] [30] Helium at low temperatures is used in cryogenics and in certain cryogenic applications.
A helium atom is an atom of the chemical element helium. Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with two neutrons, depending on the isotope , held together by the strong force .
Helium has the highest ionisation energy, so a He + ion will strip electrons off any other neutral atom or molecule. However it can also then bind to the ion produced. The He + ion can be studied in gas, or in liquid helium. Its chemistry is not completely trivial. For example, He + can react with SF 6 to yield SF + 6 or SF + 5 and atomic ...
Diatomic molecules (from Greek di- 'two') are molecules composed of only two atoms, of the same or different chemical elements. If a diatomic molecule consists of two atoms of the same element, such as hydrogen (H 2) or oxygen (O 2), then it is said to be homonuclear. Otherwise, if a diatomic molecule consists of two different atoms, such as ...
Atomicity is the total number of atoms present in a molecule of an element. For example, each molecule of oxygen (O 2) is composed of two oxygen atoms. Therefore, the atomicity of oxygen is 2. [1] In older contexts, atomicity is sometimes equivalent to valency. Some authors also use the term to refer to the maximum number of valencies observed ...
The basic idea that matter is made up of tiny indivisible particles is an old idea that appeared in many ancient cultures. The word atom is derived from the ancient Greek word atomos, [a] which means "uncuttable". But this ancient idea was based in philosophical reasoning rather than scientific reasoning.
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 ...
The helium dimer is a van der Waals molecule with formula He 2 consisting of two helium atoms. [2] This chemical is the largest diatomic molecule—a molecule consisting of two atoms bonded together. The bond that holds this dimer together is so weak that it will break if the molecule rotates, or vibrates too much.