Are the chemical properties of the elements, instead of an electron system, better explainable by a proton-neutron system of the atom? Already Mendelejew and Meyeer saw the atomic mass as causal! Until today there is a contradiction between the views of Dmitri Mendeleev and Lothar Meyer and those of Niels Bohr on the cause of the chemical properties of the elements, which has never been discussed. While Bohr and with him today's science assume that the chemical properties of the elements depend on almost massless electrons of the atomic shell, Dmitri Mendeleev and Lothar Meyer saw it quite differently. In contrast, they postulated that the chemical properties depend on the atomic mass. However, as we know today, the carriers of the atomic mass are not the electrons, but the protons and neutrons. Therefore, the question arises whether there is a proton-neutron system instead of the electron system on which the chemical properties and valences of the elements depend?
