If the products of a chemical reaction contain less potential energy than the reactants: a. energy has been stored in the molecular bonds of the product. b. energy has been released by the breaking of molecular bonds. c. the reaction will be reversible without additional energy input. d. a synthesis reaction is likely to have occurred. e. all of these choices are correct.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

the answer is 75.0%.

the answer is c

tell me if wrong