If only an element’s atomic number and weight are provided for a neutral atom, you can determine the number of protons and electrons. The atomic number indicates the number of protons, and since the atom is neutral, it also has the same number of electrons. The atomic weight (or atomic mass) provides an approximate total of protons and neutrons, but does not give you the exact number of neutrons directly.
Therefore, the correct response is:
only the number of protons and electrons.