Ions
Ions are atoms that gain or lose electrons, so that they acquire an electric charge.
The number of positive charges (protons) and negative charges (electrons)in an atom is always balances so that it can be neutral (zero net charge).
If the atoms gain one ore more electrons it will become negatively charged (excess of negative charges) and if the opposite happens, i.e., the atom loses electrons, it becomes positively charged.
The process of an atom becoming an ion is called ionization.
Examples:
negative ions (anions)
F - has 10 electrons (1 more than F)
O-2 has 10 electrons (2 more than O)
positive ions (cations)
Na+ has 10 electrons (1 less than Na)
Ca+2 has 18 electrons (2 less tha Ca)
Au+3 has 76 electrons (3 less than Au)
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