To determine the largest neutral atom you can build using the simulation, let's look at the atomic numbers of the options provided:
- Sodium (Na): Atomic number 11 (11 protons, 11 electrons)
- Fluorine (F): Atomic number 9 (9 protons, 9 electrons)
- Magnesium (Mg): Atomic number 12 (12 protons, 12 electrons)
- Neon (Ne): Atomic number 10 (10 protons, 10 electrons)
Among the options, magnesium (Mg) has the highest atomic number at 12. Therefore, the largest neutral atom you can build from the choices given is magnesium (Mg).
So the answer is: magnesium (Mg).