How do you know the charge of polyatomic ions?

What is the direction of flow of charge inside the battery? Is it different than the direction outside the battery ( in the conducting wire )?

• I was studying about this chapter currents and circuits and I want concept clarification. This is what i read - " some internal mechanism exerts force on the ions of the solution inside the battery. This force drives positive ions towards positive terminal and negative ions towards negative terminal" ............... I can see that work in done by the internal mechanism of the battery as it collecting positive charge on + terminal which is not natural and same for negative ions.  I want to know how does this un-natural ions accumulations creates current in the wire ? secondly, this charge accumulation would create an electric field ( from anode to cathode ). Wouldn't this electric field exerts an electric force on the ions which is in opposite direction to the force which the battery is doing ( because of it's internal mechanism )? If yes would't this force balance the force of battery and thus there would be no accumulation of charge ? I searched google for some answers and found that this happens in an open circuit. Please tell why it doesn't happen in closed circuit. Thirdly, please explain emf ( in context to the above questions asked ) . Wikipedia immediately jumped into formal definition and didn't answered my questions. I  just know that it is work per unit charge. Thanks in advance

• Answer:

  The current does indeed flow the other way in the battery. Think of it this way: the chemical reaction in the battery pushes negative ions to the negative terminal. Thus, there is an excess of negative charge on the negative terminal, which opposes that reaction. When the potential difference reaches 1.5 V (for a normal AA, say), the chemical reaction basically stops. Now connect a wire between the terminals. This charge can now discharge through the wire (electrons moving from negative to positive terminal). That removes the electrical potential and the chemical reaction starts up again. If you keep the wire connected that gives you continuous electrical flow. So the battery is the 'pump' that moves electrons 'uphill' that then flow 'down' again.