The theoretical yield of a reaction is the amount of product obtained if the limiting reactant is completely converted to product. Consider the reaction:
P2O5(s) + 3 H2O(l) → 2 H3PO4(aq)

If 16.62 g P2O5 is mixed with 19.90 g H2O, calculate the theoretical yield (g) of H3PO4 produced by the reaction.
(The answer needs to be in g)

"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."

increased stability in the completion of fluorine's outer shell.

it's c (engineer's do their work with mechanical stuff not on any living being)