Final answer:
An oxygen atom with an atomic mass of approximately 16 has 8 neutrons.
Step-by-step explanation:
The number of neutrons in an atom can be determined by subtracting the atomic number (which represents the number of protons) from the atomic mass (which represents the total number of protons and neutrons). Oxygen has an atomic number of 8, so it has 8 protons. The atomic mass of oxygen is approximately 16. The atomic mass is rounded to the nearest whole number, so the isotope of oxygen discussed in the question has an atomic mass of 16. Based on this information, we can subtract 8 from 16 to find that there are 8 neutrons in this isotope of oxygen.