Our Sun and all stars contain largely hydrogen and helium gases, that are fully ionized into electrons, protons (H) and helium ions (He).

But even if the atom is fully ionized, corrections are necessary.

In the outer portion of the star, the temperature gradient is shallower but the temperature is high enough that the hydrogen is nearly fully ionized, so the star remains transparent to ultraviolet radiation.

Below, most of the helium is not fully ionized, so that it radiates energy very effectively; above, it is fully ionized.

The electroosmotic flow will increase with pH until all of the available silanols lining the wall of the capillary are fully ionized.

At physiological pHs, acetic acid is usually fully ionized to acetate.

Not all plasmas are fully ionized.

In the former case, there is not enough matter in the nebula to absorb all the UV photons emitted by the star, and the visible nebula is fully ionized.

This is true of any 10M strong acid, because strong acids are fully ionized in water.

I said that "all strong acids are fully ionized in dilute solution."