F.4 Chem

An ion is an atom or molecule which has lost or gained one or more electrons, making it negatively or positively charged. An ion consisting of a single atom is called a monatomic ion. A negatively charged ion, which has more electrons in its electron shells than it has protons in its nuclei, is known as an anion due to its attraction to anodes. A positively-charged ion, which has fewer electrons than protons, is known as a cation due to its attraction to cathodes.

Ions are denoted in the same way as electrically neutral atoms and molecules except for the presence of a superscript indicating the sign of the net electric charge and the number of electrons lost or gained, if more than one. For example: H+, (SO4)2-. An alternate way of denoting charge is like this: (SO4)2-.

I hope this can help your understanding. =)

Ions is the aggregation of a great number of 'ion'
Like male & female for living things, ion exists in two different forms, positively charged ions and negatively charged ions.