What about the atomic model shown below was shown incorrect?

In an atom there are neutrons, protons and electrons. the number of protons is the atomic number . the number of neutron is the atomic mass minus atomic number. the number of electrons is the number of protons.protons and neutrons are located in the middle of the atom. and in the first ring (the ring closest to the middle) it can hold 2 electrons if there is more than two it will go to the second ring (the second ring from the middle of the atom) in the second ring it can hold eight if there is more than eight it will go to the third ring from the middle and the forth ring from the middle can hold 12 atoms . the symbol for proton = +
the symbol for neutron = it has no symbols
the symbol of electron = - .