For which of the following elements is the number of neutrons correctly represented, based on the atomic number and mass number
given? A. iron: atomic number 26, mass 56, neutrons 30 B. neon: atomic number 10, mass 20, neutrons 9 C. potassium: atomic number 19, mass 39, neutrons 19 D. phosphorus: atomic number 15, mass 31, neutrons 15
