Answer is: because they were using simple chemical reactions to transform elements, but that is possible only with nuclear reactions, which in that time were not possible to conduct.
Nuclear reactions can produce new elements, because number of protons and neutrons is changed, lead and gold have different atomic and mass numbers.
The electrons of an atom participates in a chemical reaction, chemical reactions involve the rearrangement of electrons, because there is transfer, loss, gain and sharing of electrons in chemical reactions, new elements are not formed.
Electrons are valence and free moving so they take place in charge transfer
When E° cell is an electrochemical cell which comprises of two half cells.
So,
when we have the balanced equation of this half cell :
Al3+(aq) + 3e- → Al(s) and E°1 = -1.66 V
and we have also this balanced equation of this half cell :
Ag+(aq) + e- → Ag(s) and E°2 = 0.8 V
so, we can get E° in Al(s) + 3Ag (aq) → Al3+(aq) + 3Ag(s)
when E° = E°2 - E°1
∴E° =0.8 - (-1.66)
= 2.46 V
∴ the correct answer is 2.46 V
Hydrogen because it only has one electron
