A chemist wishes to sketch potential-energy curves for (i) the covalent bond in H2 and (ii) the electrostatic attraction between isolated Na+ and Cl− ions in the gas phase (electron transfer is ignored). Which of the following combinations of relative equilibrium distance and well depth for the Na+–Cl− curve, when compared with the H–H curve, is most consistent with chemical reasoning?
a) Shorter equilibrium distance and deeper well
b) Longer equilibrium distance and shallower well
c) Longer equilibrium distance and deeper well
d) Shorter equilibrium distance and shallower well