Potassium permanganate is an ionic compound, which means that it will contain a cation, or positively charged ion, and an anion, or negatively charged ion.
You know that potassium, which is the cation, since it's used first in the name of the compound, is
But what about permanganate?
The starting point here is the suffix -ate, which is given to oxyanions, i.e .anions that contain oxygen atoms.
The maganate ion, or
Now, the prefix per- is used to show that an oxyanion contains more oxygen atoms per unit of charge than the version that simply ends in -ate.
In this case, the permanganate anion would be
Therefore, the chemical formula for potassium permanganate is