If an element has 6 protons, 6 electrons, and 8 neurons, then what’s the atomic number

The atomic mass is the number of protons, plus the number of neutrons. In this case, 8 + 6 = 14.

Explanation:

The six protons (atomic number) tells me that this is carbon; the six electrons tell me that this is a carbon atom, rather than a carbon ion (an ion is when the number of electrons does not equal the number of protons, making the atom electrically non-neutral). The eight neutrons tell me that this is an isotope (in other words, a version) of carbon called carbon-14, which happens to be mildly radioactive; and therefore useful to archaeologists in dating human artifacts.

not sure if this is what you'r looking for eubacteria and archaebacteria