A chemist must prepare 550.0mL of nitric acid solution with a pH of 0.90 at 25°C. He will do this in three steps: Fill a 550.0mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (7.0M) stock nitric acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated nitric acid that the chemist must measure out in the second step. Round your answer to 2 significant digits.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.