It's an ionic bond! Potassium is a cation, or a metal with a positive charge, and fluoride is an anion, or a nonmetal with a negative charge.
A covalent bond is the bond between two nonmetals.
Hope this helped!
Metals on the left side, metalloids on the staircase, nonmetals on right side
cesium sulfate solubility decreases with decrease in temperature (answer C) change in temperature led to the change in kinetic energy.The lower kinetic energy the lower the solubility.Decrease in temperature led to lower kinetic energy hence lowering the solubility.