Use the References to access important values if needed for this question. The element nitrogen has an atomic weight of 14.0 and consists of two stable isotopes nitrogen-14 and nitrogen-15. The isotope nitrogen-14 has a mass of 14.0 amu and a percent natural abundance of 99.6 %. The isotope nitrogen-15 has a percent natural abundance of 0.370%. What is the mass of nitrogen-15? amu