Final answer:
The characteristic that is not typical of ionic compounds is that they have low melting points. In reality, they have high melting points due to strong ionic bonds needing more energy to break, and they only conduct electricity when melted or dissolved, not in solid form.
Step-by-step explanation:
Which of the following is NOT a characteristic of most ionic compounds? The characteristic that is not common to most ionic compounds is that 'they have low melting points'. Ionic compounds actually have high melting points because the ionic bonds between the ions are very strong. Therefore, a considerable amount of energy is needed to overcome these electrostatic forces to transition the compound from the solid phase to the liquid phase. In contrast, as solid substances, ionic compounds do not conduct electricity, but they do conduct when they are melted or dissolved in water, because under these conditions, ions are free to move.
To summarize, the correct answer is B. they have low melting points. While ionic compounds are composed of metallic and non-metallic elements, they form a crystalline structure that often makes them hard and brittle. In their solid form, ionic compounds do not conduct electricity well due to the rigidity of the ionic lattice that prevents free movement of ions. However, when they are melted or dissolved, they become excellent conductors of electricity due to the mobility of the ions.