Answer: -4
Explanation: Neutrons do not matter in this problem as they have a charge of 0, or no charge. The total charge of all 17 protons will be +17 (since each proton has a charge of +1). The total charge of all 21 electrons will be -21 (since each electron has a charge of -1). Finding the difference of the charges, (+17-21) it will result in -4. This means that the atom will have an overall charge of -4.
