1. The problem statement, all variables and given/known data A 48.7 g ball of copper has a net charge of 2.2 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.). 2. Relevant equations 3. The attempt at a solution Number of electrons normally present .. (48.7/63.5)mol x 6.022^23(atoms per mol) x 29(electrons per atom) = 1.34^24 electrons Electrons removed = n ne = 2.20^-6C .. .. n = 2.20^-6C / 1.60^-19C/e .. .. n = 1.38^13 electrons removed Fraction removed = 1.38^13 removed / 1.34^24 total But the answer is wrong. I don't know what I am doing wrong?