An electrochemical cell is composed of a platinum indicator electrode and a silver-silver chloride ( Ag|AgCl ) reference electrode in a solution where the [Mn2+]/[Mn3+]=0.0743 . Calculate the cell potential if the Ag|AgCl reference electrode is replaced with a saturated calomel reference electrode (SCE). The standard reduction potential for the Mn3+/Mn2+ half-reaction is 1.56 V.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.