third way to determine how many equivalent protons there are is to look at the atom attached to. the proton (usually a carbon) and observe what that atom is bonded to, and then the atom bonded. to that, all the way until a difference is observed.
The goal of imperialism is  to exercise economic and political control over a dependent territory. Such control is often accomplished through settlement, sovereignty or less direct methods.
Although some writers would claim that direct colonial rule is a necessary part of the definition of imperialism, others would disagree. For example, they argue that the indirect political influence and economic dominance of the US constitutes imperialism, even though historically its colonial possessions have been few.