The ion polarizes the neutral atom.
Work Step by Step
This is discussed on pages 416-417, and the principles are shown in Figures 22.11 and 22.13, and discussed in Checkpoint 1. The atom is polarized, and the side closer to the charged ion acquires an induced charge opposite to that of the ion. By charge conservation, the part of the neutral atom farther from the ion acquires an induced charge that is the same as that of the ion. The opposite charges, being closer together, attract more strongly than the like charges repel. The net force is attractive.