Answer:
The formula defining the photon energies that would be emitted by transitions between the hydrogen energy levels are given by the equation:
ΔE = -13.6Z²[1/n₁² - 1/n₂²]eV, where (1 eV = 1.602×10-19 Joules) and n₁ = initial energy level and n₂ = final energy level.
Z = Atomic number of the atom
<u>Answer:</u> The half reactions are written below.
<u>Explanation:</u>
Oxidation reaction is defined as the reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.

Reduction reaction is defined as the reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.

We are given a chemical cell which is Fe-Sn cell. The half reaction follows:
<u>Oxidation half reaction:</u> 
<u>Reduction half reaction:</u> 
The substance having highest positive
potential will always get reduced and will undergo reduction reaction. Here, zinc will always undergo reduction reaction will get reduced.
<u>Total cell reaction:</u> 
Hence, the half reactions are written above.
Lithium i believe is the answer