Question

What element, and how would we write, an atom with 9 protons, 10 neutrons and 10 electrons?

Answer 1

9 protons means it is fluorine, and 10 neutrons means we write it as `"_9^19F`, but having 10 electrons, which is one more than the number of protons, means the ion has a negative charge, so `"_9^19F^-`