Which atom is more reactive, sodium or sulfur, why

Sodium is more reactive than sulfur.

Valency of Sodium is 1.

Valency of Sulfur is 2.

(Valency is the number of electrons in the outermost orbit of an atom which can be taken, given out or shared by an atom.)

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.