The type of bonding likely involved in the samples that were not conductors in their pure form but conducted a current when they mixed with water is ionic bonding. Ionic bonding occurs when one or more electrons are transferred from one atom to another, creating positively charged ions (cations) and negatively charged ions (anions). These ions are then attracted to each other and held together by electrostatic forces, forming an ionic compound.

When an ionic compound is dissolved in water, the water molecules surround and separate the ions, forming a solution that can conduct electricity. This is because the ions are free to move and carry an electrical charge. In contrast, in a pure ionic compound, the ions are held tightly together in a crystal lattice and cannot move freely, so the compound does not conduct electricity.

Examples of ionic compounds that do not conduct electricity in their pure form but do conduct electricity when dissolved in water include sodium chloride (NaCl) and potassium iodide (KI).