Question #5256c

1 Answer
Nov 2, 2015

Answer:

#"KMnO"_4#

Explanation:

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 #"K"^(+)#.

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 #"MnO"_4^(2-)#, is an oxyanion that contains manganese in the #color(blue)(+6)# oxidation state.

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 #"MnO"_4^(-)#. Here manganese is in the #color(blue)(+7)# oxidation state. Despite the fact that you still get #4# oxygen atoms, the charge of the anion is now #1-#, which means that you have moer oxygen atoms per unit of charge than in the manganate anion.

Therefore, the chemical formula for potassium permanganate is #"KMnO"_4#.