... there are 15 protons and neutrons in phosphorus. Potassium has the symbol K. Phosphorous is P. Also, she doesn't seem to know the difference between electrons and neutrons. Please do note that is is based on the data given in your question. 1 decade ago. Answer Save. There are also 15 electrons in phosphorus. Since Phosphorus has an atomic number of 15, it has 15 Protons. Lv 6. Proton number = 15. Number of neutrons = 31-15 = 16 Atomic Mass = 31. Phosphorus has 15 protons and electrons. John. Mass number = 31 = number of protons + number of neutrons. Favorite Answer. 31 = 15 + number of neutrons. Dieser wikiHow-Artikel wird dir zeigen, wie man die Anzahl von Protonen, Neutronen und Elektronen in einem Atom bestimmt. Number of electrons = 15. It also means that there are 16 neutrons in an atom of P-31. Phosphorus-33 means it has a mass number of 33. The chemical symbol for Phosphorus is P . The mass number (A) of P-31 is the sum of the protons and neutrons. Relevance. 1 0. 15 protons (all P atoms must have 15 p) and 15 electrons (the atom is neutral after all) To make up the mass to 30 we need 15 p and 15 neutrons. So there are 15 protons and 15 electrons.In P-32 isotope, there are 17 (32 - 15 = 17) neutrons Neutron number = Atomic mass - Proton number = 31 - 15 = 16 neutrons. So, in an atom of phosphorus there are 15 protons, 16 neutrons and 15 electrons. Number of protons = 15. How many protons, neutrons and electrons are there in a neutral atom pf phosphorus-30? Proton number = Electron number = 15. Phosphorus. Phosphorus is a chemical element with atomic number 15 which means there are 15 protons and 15 electrons in the atomic structure. So we have 15p,15e and 15n . 2 Answers. As an element, phosphorus exists in two major formsâ€”white phosphorus and red phosphorusâ€”but because it is highly reactive, phosphorus is never found as a free element on Earth. 18 Neutrons. Die Anzahl an Protonen und Neutronen sowie Elektronen bestimmen. Chris S. Lv 6. ===== Follow up ===== Emmie appears to be out to lunch. The number of neutrons is equal to the atomic weight - the number of protons, since both protons and neutrons weigh about 1amu, and electrons weigh almost nothing. LOL. The atomic number of phosphorus is 15. Atomic Mass = Proton Number + Neutron Number. The number of protons is the same as the number of electrons, since the charge has to balance and a proton is a +1 charge while an electron is a -1 charge. Atomic number = 15 = number of electron = number of protons. 1 decade ago.