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Oxygen-13 is an unstable isotope, with 8 protons and 5 neutrons. It has spin 3/2−, and half-life 8.58(5) ms. Its atomic mass is 13.024 815 (10) Da. It decays to nitrogen-13 by electron capture, with a decay energy of 17.770(10) MeV. Its parent nuclide is fluorine-14.
Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [68] About 0.9% of the Sun's mass is oxygen. [19] Oxygen constitutes 49.2% of the Earth's crust by mass [69] as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust.
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]
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.
Examples include carbon-14, nitrogen-15, and oxygen-16 in the table above. Isobars are nuclides with the same number of nucleons (i.e. mass number) but different numbers of protons and neutrons. Isobars neighbor each other diagonally from lower-left to upper-right. Examples include carbon-14, nitrogen-14, and oxygen-14 in the table above.
The chemists used an "atomic mass unit" (amu) scale such that the natural mixture of oxygen isotopes had an atomic mass 16, while the physicists assigned the same number 16 to only the atomic mass of the most common oxygen isotope (16 O, containing eight protons and eight neutrons).
Protons and neutrons, ... Heavy oxygen (17 O), not carbon or fluorine, is the product. This was the first reported nuclear reaction, 14 N + α → 17 O + p.
118 chemical elements have been identified and named officially by IUPAC.A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z).