Final answer:
In a single displacement reaction, an element in the activity series can replace any element below it.
Step-by-step explanation:
For a single-replacement reaction, a given element is capable of replacing an element that is below it in the activity series. In a single displacement reaction, an element in the activity series can replace any element below it. This can be used to predict if a reaction will occur.
Suppose that small pieces of the metal nickel were placed into two separate aqueous solutions: one of iron (III) nitrate and one of lead (II) nitrate.
Looking at the activity series, we see that nickel is below iron, but above lead. Therefore, the nickel metal will be capable of replacing the lead in a reaction, but will not be capable of replacing iron.