And atom of which element has the largest atomic radius

Francium  

Step-by-step explanation:

Atomic radius increases from right to left in a Period and from top to bottom of a Group in the Periodic Table.

Thus, the atom with the largest atomic radius is in the lower left corner.

Francium, with an atomic radius of 348 pm, has the largest atomic radius of any element in the Periodic Table.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

i'm wiling to try and you : )