Question

How does the Cahn-Ingold-Prelog system work?

Answer 1

Here is a great picture:

So the name of this compound is Z 1-bromine-2-chlorineethane. Why Z? Because the atoms or supstituent with the highest priority are on the same side. If not, then it would be E.

Z- zusammen (german)
E- entgegen (german)