If the force between an electron and a proton in a vacuum is -1.40E-22 N, how far apart are they?

Electromagnetic force :

1.4*10^-22 = 9*10^9*1.60^2*10^-38/d^2

d = √ (9*10^9*1.60^2*10^-38)/(1.4*10^-22) = 1.28 mm which is impossible 

Gravitational force :

mass of electron me = 9.10*10^-31 kg

mass of proton mp = 1.67*10^-27 kg 

1.4*10^-22 = me*mp*G/d^2

d = √9.1*1.67*10^-58*6.67*10^-11*10^22/1.4 = 2.7*10^-23 m   which is impossible 

the true distance between proton and electron is in the order of magnitude 10^-12 m 

F = kQ₁Q₂/r² = 1.4e-22

r² = (9e9)(1.602e-19)²/1.4e-22

r = (1.602e-19)√(9e9/1.4e-22)

r = 0.00128 m

or 1.28 mm

Coulomb's law, force of attraction/repulsion

F = kQ₁Q₂/r²

   Q₁ and Q₂ are the charges in coulombs

   F is force in newtons

   r is separation in meters

   k = 8.99e9 Nm²/C²

1 electron charge = 1.602e-19 C