15. KF has an ionic bond with a bond length of 0.217nm. Calculate the AE in kj/mol, for the formation of a KF bond from the neutral atoms K and F. For this calculation, assume that the potassium and fluorine ions are point charges. Ionization Energy and Electron Affinity for K and F are provided in the table below.

 [Hint: Overall: K+F →KF ； ε₀= 8.854×10^-12 C²/J-m; e =1.602×10^-19 C]

 
(A) -5.50×10^-² J/mol,
(B) -55 J/mol,
(C) -550 J/mol,
(D) -550 kJ/mol,
(E) -5,500 kJ/mol