Final answer:
Potassium nitrate is classified as an electrolyte because it dissociates into electrically charged ions, potassium (K+) and nitrate (NO3-), which allow it to conduct electricity when dissolved in water.
Step-by-step explanation:
Potassium nitrate is classified as an electrolyte because it dissociates into ions when dissolved in water. Potassium (K), with an atomic number of 19, easily donates its one valence electron, resulting in a positively charged potassium ion, K+. This ion is a cation. Similarly, the polyatomic nitrate ion, NO3-, which is held together by polar covalent bonds, combines with the potassium cation to form the ionic compound potassium nitrate, KNO3. The dissociation of potassium nitrate in water into K+ and NO3- ions enables it to conduct electricity, a characteristic behavior of electrolytes.