2. Moving positive charges Ions moving in an electrolyte Electrolysis of Copper Chloride (CuCl 2 )

3. What is an ion? An ion is an atom which has gained or lost one or more electrons in its outer electron shell. These atoms haven’t got the same number of electrons and protons, therefore become negatively charged (if they gained electrons), or positively charged (if they lost electrons) Cu 2+ Cl - Copper ion: two electrons lostChlorine ion: one electron gained

4. Copper Chloride solution When dissolved in water copper chloride (CuCl 2 ) splits into one ion of Copper and two ions of Chlorine. Cu Cl Cu 2+ Cl - So, we now have a solution of positive and negative ions free to move in the solvent (water)

5. Electrolysis of Copper Chloride If we apply a difference of potential to the solution we notice a movement of charges. Copper ion (+2) Chlorine ion (-1) Write a + and a – on the corrent terminals Write Cu +2 and Cl -1 on the terminals on which they collect respectively Show with a blue arrow the direction of the free electrons in the circuit and with a red arrow the direction of the electric current