In chemistry and physics, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
N= m/Mr
Find the Mr of C3H8NO5P and then divide the mass by the Mr.
Sorry I don't have periodic table with me so I can't calculate the Mr for you
