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  2. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    2 combines with atomic oxygen made by the splitting of O 2 by ultraviolet (UV) radiation. [22] Since ozone absorbs strongly in the UV region of the spectrum, the ozone layer of the upper atmosphere functions as a protective radiation shield for the planet. [22] Near the Earth's surface, it is a pollutant formed as a by-product of automobile ...

  3. Allotropes of oxygen - Wikipedia

    en.wikipedia.org/wiki/Allotropes_of_oxygen

    There are several known allotropes of oxygen. The most familiar is molecular oxygen (O 2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O 3). Others are: Atomic oxygen (O 1), a free radical. Singlet oxygen (O * 2), one of two metastable states of ...

  4. Oxide - Wikipedia

    en.wikipedia.org/wiki/Oxide

    Notice that oxygen forms three bonds to titanium and titanium forms six bonds to oxygen. An oxide (/ ˈ ɒ k s aɪ d /) is a chemical compound containing at least one oxygen atom and one other element [1] in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of –2) of oxygen, an O 2– ion with oxygen in the ...

  5. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    A chemical element is a chemical substance whose atoms all have the same number of protons.The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus.

  6. Isotopes of oxygen - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_oxygen

    Oxygen-15 is a radioisotope, often used in positron emission tomography (PET). It can be used in, among other things, water for PET myocardial perfusion imaging and for brain imaging. [20] [21] It has an atomic mass of 15.003 0656 (5), and a half-life of 122.266(43) s. It is produced through deuteron bombardment of nitrogen-14 using a cyclotron ...

  7. Atomic ratio - Wikipedia

    en.wikipedia.org/wiki/Atomic_ratio

    The atomic ratio is a measure of the ratio of atoms of one kind (i) to another kind (j). A closely related concept is the atomic percent (or at.%), which gives the percentage of one kind of atom relative to the total number of atoms. [1] The molecular equivalents of these concepts are the molar fraction, or molar percent.

  8. Ozone–oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Ozone–oxygen_cycle

    Ozone–oxygen cycle in the ozone layer: 1. Oxygen photolyzed to atomic oxygen 2. Oxygen and ozone continuously interconverted. Solar UV breaks down oxygen; molecular and atomic oxygen combine to form Ozone. 3. Ozone is lost by reaction with atomic oxygen (plus other trace atoms).

  9. Oxygen-16 - Wikipedia

    en.wikipedia.org/wiki/Oxygen-16

    Oxygen-16 (symbol: 16 O or 16 8 O) is a nuclide. It is a stable isotope of oxygen, with 8 neutrons and 8 protons in its nucleus, and when not ionized, 8 electrons orbiting the nucleus. Oxygen-16 has a mass of 15.994 914 619 56 u. It is the most abundant isotope of oxygen and accounts for 99.757% of oxygen's natural abundance. [2]