I’m confused what are you asking exactly?
The mass number of an atom is basically the total number of protons and neutrons.
Solution :
A cell that is concentrated is constructed by the same half reaction for the anode as well as he cathode.
We know,
In a standard cell,
the reduction half cell reaction is :

The oxidation half ell reaction :

Thus the complete reaction of the cell is :

cell = 
2.469 could be maid dont forget to hit that thanks button
A) B). That’s it I hope it’s help.