29 protons and 27 electrons. Since the element is copper, that automatically means that you have 29 protons. Any other number would be an element other than copper. The 2+ indicates that the ion has a positive charge of 2. So it is missing 2 electrons. Since a neutral atom would have 29 electrons and you're missing 2, the number of electrons will be 29 - 2 = 27 So the answer is 29 protons and 27 electrons.