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  2. Calcium - Wikipedia

    en.wikipedia.org/wiki/Calcium

    A calcium atom has twenty electrons, with electron configuration [Ar]4s 2. Like the other elements placed in group 2 of the periodic table, calcium has two valence electrons in the outermost s-orbital, which are very easily lost in chemical reactions to form a dipositive ion with the stable electron configuration of a noble gas, in this case ...

  3. Isotopes of calcium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_calcium

    About 2 g of calcium-48. Calcium-48 is a doubly magic nucleus with 28 neutrons; unusually neutron-rich for a light primordial nucleus. It decays via double beta decay with an extremely long half-life of about 6.4×10 19 years, though single beta decay is also theoretically possible. [7]

  4. Electron shell - Wikipedia

    en.wikipedia.org/wiki/Electron_shell

    The term may also refer to the shield-connecting part of D-sub connectors. In chemistry and atomic physics, an electron shell may be thought of as an orbit that electrons follow around an atom 's nucleus. The closest shell to the nucleus is called the "1 shell" (also called the "K shell"), followed by the "2 shell" (or "L shell"), then the "3 ...

  5. Electron configuration - Wikipedia

    en.wikipedia.org/wiki/Electron_configuration

    In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. [ 1 ] For example, the electron configuration of the neon atom is 1s2 2s2 2p6, meaning that the 1s, 2s, and 2p subshells are occupied by two, two, and six ...

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods ") and columns (" groups "). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order ...

  7. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    In chemistry and physics, valence electrons are electrons in the outermost shell of an atom, and that can participate in the formation of a chemical bond if the outermost shell is not closed. In a single covalent bond, a shared pair forms with both atoms in the bond each contributing one valence electron. The presence of valence electrons can ...

  8. Calcium in biology - Wikipedia

    en.wikipedia.org/wiki/Calcium_in_biology

    Calcium in biology. Calcium is used in many nerves in the voltage-gated calcium channel which is slightly slower than the voltage-gated potassium channel. It is most notably used in the cardiac action potential. [1] Calcium ions (Ca 2+) contribute to the physiology and biochemistry of organisms' cells. They play an important role in signal ...

  9. Alkaline earth metal - Wikipedia

    en.wikipedia.org/wiki/Alkaline_earth_metal

    The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). [ 1 ] The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.