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  2. Table of nuclides - Wikipedia

    en.wikipedia.org/wiki/Table_of_nuclides

    A table or chart of nuclides is a two-dimensional graph of isotopes of the elements, in which one axis represents the number of neutrons (symbol N) and the other represents the number of protons (atomic number, symbol Z) in the atomic nucleus. Each point plotted on the graph thus represents a nuclide of a known or hypothetical chemical element.

  3. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    Magne­sium 12 Mg 24.305: Alumin­ium ... Atoms with the same number of protons but different numbers of neutrons are called isotopes of the same ... g h i n = 1 1s 2 ...

  4. Mass number - Wikipedia

    en.wikipedia.org/wiki/Mass_number

    For example, uranium-238 usually decays by alpha decay, where the nucleus loses two neutrons and two protons in the form of an alpha particle. Thus the atomic number and the number of neutrons each decrease by 2 ( Z : 92 → 90, N : 146 → 144), so that the mass number decreases by 4 ( A = 238 → 234); the result is an atom of thorium-234 and ...

  5. List of chemical elements - Wikipedia

    en.wikipedia.org/wiki/List_of_chemical_elements

    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). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...

  6. Stable nuclide - Wikipedia

    en.wikipedia.org/wiki/Stable_nuclide

    Stable even–even nuclides number as many as three isobars for some mass numbers, and up to seven isotopes for some atomic numbers. Conversely, of the 251 known stable nuclides, only five have both an odd number of protons and odd number of neutrons: hydrogen-2 , lithium-6, boron-10, nitrogen-14, and tantalum-180m.

  7. Magnesium - Wikipedia

    en.wikipedia.org/wiki/Magnesium

    Chemical element with atomic number 12 (Mg) Magnesium, 12 Mg Magnesium Pronunciation / m æ ɡ ˈ n iː z i ə m / (mag- NEE -zee-əm) Appearance shiny grey solid Standard atomic weight A r °(Mg) [24.304, 24.307] 24.305 ± 0.002 (abridged) Magnesium in the periodic table Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus ...

  8. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    Different isotopes of a given element are distinguished by their mass number, which is written as a superscript on the left hand side of the chemical symbol (e.g., 238 U). The mass number is always an integer and has units of "nucleons". Thus, magnesium-24 (24 is the mass number) is an atom with 24 nucleons (12 protons and 12 neutrons).

  9. Atomic mass - Wikipedia

    en.wikipedia.org/wiki/Atomic_mass

    protons and neutrons have different masses, [7] [8] and different nuclides have different ratios of protons and neutrons. atomic masses are reduced, to different extents, by their binding energies. The ratio of atomic mass to mass number (number of nucleons) varies from 0.998 838 1346 (51) for 56 Fe to 1.007 825 031 898 (14) for 1 H.