Which of the following pairs of elements is most likely to form a covalent bond? a. sodium and chlorine b. magnesium and oxygen c. phosphorus and bromine d. copper and oxygen

its first and third is your answer i did the qustion the fourth isnt right

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.