Calculate the force of attraction between a K+ and an O2- ions, the centres of which are separated by an equilibrium distance of r. = 1.5 nm. Given the attractive energy (21e) (Z2e) between two ions, in standard symbols, is EA = where electron charge, e = 1.602x 10-19 Coulombs; Permittivity of vacuum, &i=8.85 x 10-12 F/m = 4πεrhoY ng