Flexi Says: The quantum mechanical model of the atom comes from the solution to Schrödinger’s equation. Schrödinger's wave function described not the electron but rather all its possible states, and thus could be used to calculate the probability of finding an electron at any given location around the nucleus. This reconciled the two opposing theories of particle versus wave electrons and the idea of wave–particle duality was introduced. This theory stated that the electron may exhibit the properties of both a wave and a particle. For example, it can be refracted like a wave, and has mass like a particle. The location of the electrons in the quantum mechanical model of the atom is often referred to as an electron cloud. They are a type of fundamental particles called leptons. All leptons have an electric charge of -1 or 0. Inside the nucleus of an atom, there are protons and neutrons. Protons consist of 2 up and 1 down quarks and gluons while neutrons contains 1 up and 2 down quarks and gluons as fundamental particles.