b) Electric current

• explain what is meant by electric current in metals

• the movement of electrons

• describe the structure of a metal

• most electrons are fixed to their atoms + some electrons are free to move

• metallic structure → lattice of positive ions surrounded by delocalised electrons

• explain what is meant by electric current in electrolytes

• the movement of ions

• describe the structure of an electrolyte

• a molten or aqueous ionic solution

• describe the decomposition of an electrolyte

• electrolyte → separates into positive and negative ions → which are attracted to the cathode and anode

• define conventional current

• the representation of electric current as travelling from the positive to the negative terminal

• describe the relation between electric current in metals and conventional current

• electric current in metals → travels from the negative to the positive terminal

• opposite to the direction of conventional current

• describe the relation between electric current in electrolytes and conventional current

• electric current in electrolytes → can travel from the positive to the negative or from the negative to the positive terminal

• either in the same direction or in the opposite direction of conventional current