Final answer:
Oxygen-16 has 8 protons, 8 neutrons, and 8 electrons.
Step-by-step explanation:
Oxygen-16, denoted as ¹⁶₈O, has 8 protons, 8 neutrons, and 8 electrons. The atomic number of an element indicates the number of protons it has. In the case of oxygen, the atomic number is 8. Neutrons are found in the nucleus of an atom and their number can be calculated by subtracting the atomic number from the mass number. In this case, the mass number of oxygen-16 is 16, so the number of neutrons is 16 - 8 = 8. Electrons, which are negatively charged particles, are equal in number to the number of protons in a neutral atom. Therefore, oxygen-16 has 8 electrons.