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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. Ion - Wikipedia

    en.wikipedia.org/wiki/Ion

    Electron transfer between lithium (Li) and fluorine (F). Forming an ionic bond, Li and F become Li + and F − ions. An ion (/ ˈaɪ.ɒn, - ən /) [1] is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is ...

  4. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    Similar to a core electron, a valence electron has the ability to absorb or release energy in the form of a photon. An energy gain can trigger the electron to move (jump) to an outer shell; this is known as atomic excitation. Or the electron can even break free from its associated atom's shell; this is ionization to form a positive ion. When an ...

  5. Ionization - Wikipedia

    en.wikipedia.org/wiki/Ionization

    Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules, electrons, positrons, [1] protons, antiprotons [2] and ions, [3][4][5][6][7][8][9] or through the interaction with electromagnetic radiation. Heterolytic bond cleavage and heterolytic substitution reactions can ...

  6. Octet rule - Wikipedia

    en.wikipedia.org/wiki/Octet_rule

    The bonding in carbon dioxide (CO 2): all atoms are surrounded by 8 electrons, fulfilling the octet rule.. The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.

  7. Ionic bonding - Wikipedia

    en.wikipedia.org/wiki/Ionic_bonding

    Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities, [1] and is the primary interaction occurring in ionic compounds. It is one of the main types of bonding, along with covalent bonding and metallic bonding.

  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. Metal ions in aqueous solution - Wikipedia

    en.wikipedia.org/wiki/Metal_ions_in_aqueous_solution

    A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M (H 2 O) n] z+. The solvation number, n, determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table. Lanthanide and actinide aqua ions have higher solvation numbers ...