Examples of polyatomic ions are Acetate (CH 3 COO – ), Phosphate (PO 4 3- ), Permanganate (MnO 4 – ) , Oxalate (C 2 O 4 2- ) etc.

The is made up of two or more atoms, it can be referred to as a polyatomic ion or a molecular ion. Depending on the charge it may be classified as...

Phosphate (PO 4 3- ) is a polyatomic ion carrying a negative charge. The phosphate ion made more than one atom.

The ion is made up of only one type of atom each holding some net charge, positive or negative, it can be referred to as a monatomic ion.

No Mg 2+ ion is a monatomic ion, it is made up of only one Mg atom.