Atomic Structure

The mass of a neutron is about the same as that of a proton. A neutron is a subatomic particle with no net electric charge and a mass slightly greater than that of a proton. Together with protons, neutrons make up the nucleus of an atom. The mass of a neutron is 1.67492749804 × 10−27 kg, which is slightly greater than the mass of a proton, which is 1.672621777 × 10−27 kg. The mass of an electron is much smaller, at 9.10938356 × 10−31 kg.