Question

why do ionic compounds conduct electricity in aqueous solution or when molten, but do not conduct electricity when in the solid state

Answer 1

ionic compounds when in solution /aqueous solution --> form ions such as Cation and Anion which are charged as + and - .

Simlar to this, molten ionci compounds will be able to move arround freely in cation/anions.. Recall that we need movement of cations/anions in order to move charge from valence electrons...

These are electrolytes, will allow electrons to flow readily in solution.

In solid state; ions are STEADY, and will not be able to move, i.e. donate e- attract/reppeal each other, they are in a fixed crystal lattice.

This is why there is no conductivity in ionic compounds when solid