Most atoms do not have actually eight electrons in your valence electron shell. Part atoms have actually only a few electrons in their outer shell, while some atoms lack only one or 2 electrons to have an octet. In situations where one atom has three or under valence electrons, the atom may lose those valence electrons quite quickly until what continues to be is a reduced shell that includes an octet. Atom that shed electrons obtain a confident charge together a resultbecause they room left v fewer negatively charged electrons come balance the confident charges the the proton in the nucleus. Positively charged ion are called cations. Many metals become cations when they make ionic compounds.

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Cations

A neutral salt atom is most likely to accomplish an octet in the outermost shell by shedding its one valence electron.

\<\ceNa \rightarrow Na^+ + e^-\>

The cation produced in this way, Na+, is called the sodium ion to identify it indigenous the element. The outermost shell of the sodium ion is the second electron shell, which has actually eight electron in it. The octet rule has been satisfied. Number \(\PageIndex1\) is a graphical explicate of this process.

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

The name for optimistic and an adverse ions space pronounced CAT-eye-ons and ANN-eye-ons, respectively.

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In plenty of cases, aspects that belong come the same group (vertical column) ~ above the routine table type ions v the same charge due to the fact that they have the same variety of valence electrons. Thus, the regular table becomes a device for mental the dues on many ions. Because that example, all ions made native alkali metals, the first column top top the periodic table, have a 1+ charge. Ion made native alkaline earth metals, the 2nd group on the periodic table, have actually a 2+ charge. Top top the various other side the the periodic table, the next-to-last column, the halogens, type ions having actually a 1− charge. Number \(\PageIndex3\) shows how the charge on numerous ions deserve to be suspect by the place of an aspect on the periodic table. Keep in mind the convention of an initial writing the number and then the authorize on a ion through multiple charges. The barium cation is created Ba2+, no Ba+2.