Emergent properties arise when more than one part works together and these are properties not obvious from the nature of the individual parts. The various individual parts of electron transport are not capable of making ATP, nor is the ATP synthase capable of doing this by itself. Nor, for that matter, is the membrane in which they are all placed capable of producing ATP alone. However, when they work in the proper order, they can generate a proton gradient which can then be used to make ATP from the energy in that gradient.
Work Step by Step
This question is asking you to go back and review the material in Ch. 1 on emergent properties and to find and explain that concept in how chemiosmosis works. Consider how the components/steps to an end result may differ from that result, and how this relates to the concept of an emergent property being different than the properties of its parts.