Most atoms perform not have eight electron in their valence electron shell. Some atoms have only a couple of electrons in their external shell, while part atoms lack only one or two electrons to have actually an octet. In situations where an atom has three or under valence electrons, the atom may lose those valence electron quite quickly until what remains is a reduced shell that has an octet. Atoms that shed electrons get a hopeful charge as a resultbecause they are left with fewer negatively fee electrons come balance the optimistic charges that the proton in the nucleus. Positively charged ion are dubbed cations. Many metals come to be cations as soon as they make ionic compounds.

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Cations

A neutral salt atom is likely to achieve an octet in that is outermost covering by losing its one valence electron.

The cation developed in this way, Na+, is dubbed the sodium ion to distinguish it indigenous the element. The outermost covering of the sodium ion is the second electron shell, which has actually eight electrons in it. The octet dominion has been satisfied. Figure (PageIndex1) is a graphical relenten of this process.

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api/deki/files/114134/3.2B.jpg?revision=1" />Figure (PageIndex2): The formation of a Chlorine Ion. On the left, the chlorine atom has actually 17 electrons. Top top the right, the chloride ion has actually 18 electrons and also has a 1− charge.

The name for optimistic and negative ions room pronounced CAT-eye-ons and ANN-eye-ons, respectively.

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In many cases, facets that belong come the same team (vertical column) ~ above the regular table type ions with the very same charge due to the fact that they have the same number of valence electrons. Thus, the regular table becomes a tool for mental the dues on countless ions. For example, all ions made native alkali metals, the very first column ~ above the periodic table, have a 1+ charge. Ions made native alkaline planet metals, the second group top top the periodic table, have a 2+ charge. ~ above the other side that the periodic table, the next-to-last column, the halogens, form ions having a 1− charge. Number (PageIndex3) shows how the charge on numerous ions have the right to be guess by the location of an element on the routine table. Note the convention of an initial writing the number and then the authorize on a ion with multiple charges. The barium cation is created Ba2+, not Ba+2.