A chemical formula identifies each constituent element by its chemical symbol and indicates the proportionate number of atoms of each element.
<em>For example, the empirical formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom.</em>
Metals naturally form cations.
<span>Thomson studied electric discharge in a vacuum and found that the deflection of rays was evidence of atoms containing much smaller particles. He calculated that these particles would have a large charge in relation to their mass. While he did not name electrons, he knew they existed.</span>

Thus 174 protons would make at most 6 copper atoms. However, it would take 174 extra electrons (29 per atom) and even more neutrons than that to construct neutral copper atoms with stable nuclei.
The answer Fam is B) Models