Show step by step solution using the F attractive formulaFinal answer given 9.16x10^-9 N

Calculate the attractive force between of Ba?+ and $2- ions that just touch b each other. Assume the ionic radius of Ba?* and S2- are 0.143 nm and 0.174 nm respectively. (Given, k = 9 x 109 Nm2C-2, electron charge, e = 1.6 x 10-19 C)