Final answer:
In a negative ion like O²⁻, there are more electrons than protons. A neutral oxygen atom has 8 protons and the same number of electrons to be neutral. A 2- charge indicates an extra 2 electrons, totaling 10 electrons for oxygen in this case.
Step-by-step explanation:
When considering an anion with the symbol O2-, we understand that we are dealing with a case where an atom has gained extra electrons. Neutral atoms must have an equal number of protons and electrons to balance out their charges. For instance, a neutral oxygen atom has an atomic number of 8, meaning it has 8 protons; in a neutral state, it would also have 8 electrons.
However, the negative ion O2- indicates that the oxygen atom has gained 2 additional electrons, giving it a total of 10 electrons. This results in a disparity where the number of electrons exceeds the number of protons, giving the ion a negative charge. Therefore, in a negative ion such as O2-, there is a higher number of electrons compared to protons.