Answer:
11 Protons, 12 Neutrons, 11 Electrons.
Step-by-step explanation:
The number of protons is the same as the atomic number for any element. Since protons and neutrons both weigh about 1amu, if we subtract 11 from 23, we can find the mass of the neutrons which is 12. Since we know that the atom is a neutral atom, there is no charge which tells us that the number of protons and electrons are the same.