Final answer:
One molecule of potassium nitrate contains 9 atoms.
Step-by-step explanation:
The correct answer is c. 9.
Potassium nitrate, with the chemical formula KNO3, consists of one potassium atom (K), one nitrogen atom (N), and three oxygen atoms (O). Therefore, it has a total of nine atoms.
Here is the breakdown of the atoms in one molecule of potassium nitrate:
1 potassium atom (K)
1 nitrogen atom (N)
3 oxygen atoms (O)
So, the answer is c. 9.