Final answer:
A neutral atom must have an equal number of protons (positively charged) and electrons (negatively charged). For an atom with 12 protons, it must also have 12 electrons to maintain neutrality. Neutrons do not affect electrical neutrality, as they are uncharged.
Step-by-step explanation:
If an atom has 12 positively charged subatomic particles, it must also have 12 negatively charged subatomic particles to be considered a neutral atom. These negatively charged particles are known as electrons. A neutral atom has an equal number of protons, which are positively charged, and electrons, which are negatively charged. This balance ensures that the overall charge of the atom is zero. Since the question specifies positively charged particles, we refer to them as protons. Therefore, to be neutral, the atom must also have the same number of electrons as protons.
For instance, a magnesium atom, which has an atomic number of 12, will have 12 protons. For it to be neutral, it must also have 12 electrons. Neutrons do not have a charge and their number can vary in different isotopes without affecting the electrical neutrality of the atom. However, for an atom to be neutral, it simply needs to have an equal number of electrons and protons.