An ion is an atom or a collection of atoms that collectively have a positive or negative charge. They gain positive or negative charges by donating or accepting electrons. Those charges help to attract other ions, which eventually form bonds, called ionic bonds.
Sodium chloride, or table salt, is another example of an ionic bond. The sulfate ion is actually a collection of atoms, sulfur and oxygen. The sulfate ion has two negative ends, meaning it donates an electron on each side from the oxygen atoms.Learn more about Chemistry