* 8 protons: These are positively charged particles that determine the element's identity. Since oxygen has an atomic number of 8, it always has 8 protons.

* 8 neutrons (most commonly): These are neutral particles that contribute to the atom's mass. While the most common isotope of oxygen has 8 neutrons, other isotopes exist with varying numbers of neutrons.

It's important to note: The number of neutrons can vary, creating different isotopes of oxygen. However, the number of protons always remains the same for an oxygen atom.