Defining Current
- Electric current is the rate of flow of charge carriers
- This is defined as the movement of
- Electrons in metals
- Ions in electrolytes
Electrons in Metals
- In metals, such as copper, mercury and titanium, the flow of charge is made up of electrons
- The metal ions are closely packed and arranged in a crystal lattice structure
- The atoms have many free (delocalised) electrons that are free to move randomly
- These are sometimes known as conduction electrons
- These are what makes metals good conductors of electricity
- When conducting electricity, meaning one side of the metal is attaching to a negative terminal and the other to a positive, the conduction electrons drift slowly through the metal creating a current
Free electrons in metal create current flow
Ions in Electrolytes
- Ions are atoms that have lost or gained an electron. This means they are either:
- An anion - a negative ion (gained an electron)
- A cation - a positive ion (lost an electron)
- An electrolyte is a substance that produces an electrically conducting solution
- The charge carriers are not electrons, but cations and anions
- An example of an electrolyte is copper sulfate dissolved in water
Anions are attracted to the anode and cations to the cathode