Difference between Potassium Perchlorate and Potassium Chlorate?

-->Oh yes there is a difference. But keep one thing in mind. 'Per' means adding one extra 'o' (Oxygen) to the existing compound.

--> Suppose that a recipe calls for 1 tbsp. of baking powder and you add 2 tbsp. or 1/2 tbsp. of the ingredient, your item will be a flop. Same way in chemistry, using a totally different compound will result in a completely new product (WHICH IS NOT WHAT YOU DESIRED)

--> The experiment may or may not become unstable depending on what you use. But as I said, you won't get your desired products.

I hope this helps!

Potassium chlorate is a compound containing potassium,chlorine and oxygen, with the chemical formula K[ClO3]. In pure form, it is a white crystalline substance. It is the most common chlorate in industrial use, and is usually present in well-stocked laboratories. It is used:as an oxidizing agent, to prepare oxygen, as a disinfectant, especially in bleach, in safety matches, and in explosives and fireworks. Potassium perchlorate, chemical formula KClO4, is a strong oxidizer. It is a colorless, crystalline substance that melts at about 610 °C. It is one of the most common oxidizers used in fireworks, ammunition percussion caps, explosive primers, and is used variously in propellants, flash compositions, stars, and sparklers. It has been used as a solid rocket propellant, though in that application it has mostly been replaced by the higher performance ammonium perchlorate. KClO4 has the lowest solubility of all perchlorates (2.08 g KClO4 in 100 g H2O at 25 deg C).It has a molar mass of 138.55 g/mol.

the difference would be the oxygen.

KClO= Potassium HypoChlorite

KClO2= Potassium Chlorite

KClO3= Potassium Chlorate

KClO4= Potassium Perchlorate

The Per comes from Hyper- but the Hy is droped.

As far as your other ? it would be stable but just a totaly different compound it would be called Potassium Nitrate the oxidation numbers just have to balance