Explain why ionic compounds (e.g. NaCl) are soluble, and why they conduct electricity in this state.

Ionic compounds have a 'giant' ionic lattice structure. 'Giant' just essentially means that a basic unit is being repeated. In the case of NaCl, the ionic lattice would consist of the ions Na+ and Cl-. Water molecules are polar: the hydrogen atoms have a partial positive charge (δ+), and the oxygen atom has a partial negative charge (δ-). The polar water molecule would attract their opposite ions within the lattice. The δ- oxygen would attract a Na+ ion, and the δ+ hydrogen would attract a Cl- ion. This attraction would pull away and break apart the ions within the lattice, resulting in the ionic compound being dissolved.When ionic compounds are molten or in solution (aqueous), they conduct electricity. Ionic compounds consist of ions, e.g. in NaCl the ions are Na+ and Cl-. When these ions are free to move they can carry a charge/current, which is only possible in their molten or soluble state. When the ionic compounds are in their solid state, their ions are held by strong ionic bonds, so the ions cannot move and therefore the compound does not conduct electricity.