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Formation of cation

Atoms Molecules Ions Chemical Equations On-line practice



Sodium (Group 1)

No. of electrons : 11

No. of protons : 11

bulletSodium has 3 orbits.
bulletThe third orbit has 1 electron.
bulletFor sodium to be stable, it can either give away the only electron it has in the third orbit OR it can receive 7 more electrons from other atoms in order for it to have 8 electrons on the outer orbit.
bulletBoth processes would have sodium ending up with 8 electrons on its outer orbit.
bulletHowever, giving away 1 electron is more favourable than receiving 7 electrons.
bulletTherefore, sodium will lose 1 electron which means that it now has 10 electrons and 11 protons.  This makes sodium to have a positive charge.
bulletNa - 1e --> Na+ 


Other common cations :

Ca - 2e --> Ca 2+ 

Mg - 2e --> Mg 2+

K - 1e --> K +


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