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  2. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are ...

  3. Nitrate - Wikipedia

    en.wikipedia.org/wiki/Nitrate

    The nitrate anion is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a formal charge of −1. [citation needed] This charge results from a combination formal charge in which each of the three oxygens carries a ...

  4. Nitrogen - Wikipedia

    en.wikipedia.org/wiki/Nitrogen

    Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N 2, a colourless and odourless diatomic ...

  5. Molar ionization energies of the elements - Wikipedia

    en.wikipedia.org/wiki/Molar_ionization_energies...

    This is the energy per mole necessary to remove electrons from gaseous atoms or atomic ions. The first molar ionization energy applies to the neutral atoms. The second, third, etc., molar ionization energy applies to the further removal of an electron from a singly, doubly, etc., charged ion. For ionization energies measured in the unit eV, see ...

  6. Isotopes of oxygen - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_oxygen

    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.

  7. Molar concentration - Wikipedia

    en.wikipedia.org/wiki/Molar_concentration

    Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular, of a solute in a solution, in terms of amount of substance per unit volume of solution. In chemistry, the most commonly used unit for molarity is the number of moles per liter ...

  8. Oxyanion - Wikipedia

    en.wikipedia.org/wiki/Oxyanion

    Oxyanion. Negatively charged polyatomic ion containing oxygen. An oxyanion, or oxoanion, is an ion with the generic formula A. xOz−. y (where A represents a chemical element and O represents an oxygen atom). Oxyanions are formed by a large majority of the chemical elements. [1]

  9. Noble gas - Wikipedia

    en.wikipedia.org/wiki/Noble_gas

    Nitrogen: Oxygen: Fluorine: ... The simplest is the helium hydride molecular ion, ... change in the noble gas concentration and their isotopic ratios can be used to ...