Which nonmetal is extremely nonreactive, refusing to bond with other elements except under very unusual conditions created in the laboratory?

Xenon
Sulfur
Oxygen
Chlorine

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.