A materials-analysis record describes a neutral atom with 6 protons, 7 neutrons and 6 electrons.
Which entry correctly describes the atom's central region?
It contains 6 protons and 7 neutrons and has relative charge 0.
It contains 6 protons and 7 neutrons and has relative charge +6.
It contains 6 protons and 6 electrons and has relative charge 0.
It contains 7 neutrons and 6 electrons and has relative charge −6.