What is the electrostatic force between an electron and a proton separated by 0.1 mm? 2.3 x 10-20 N, attractive. 2.3 x 10-20 N, repulsive. 2.3 x 10-18 N, attractive. 2.3 x 10-18 N, repulsive. O 2.3 10-16 N, attractive.