Need help answering this question, check the picture

A single replacement reaction occurs when an element reacts with a compound to produce a new element and a new compound. It can only occur when the element that is doing the replacing is more reactive than the element that is being replaced. Therefore, it is useful to have a list of elements in order of their relative reactivities. The activity series is a list of elements in decreasing the order of reactivity. Since metals replace other metals, while nonmetals replace other nonmetals, they each have a separate activity series.

There are two types of single replacement reactions:

A metal replaces another metal that is in solution:  

A + BC → B + AC

Example:  Zn + CuC → Cu + ZnC

A halogen replaces another halogen that is in solution:

A + BC → C + BA

Example: Br + 2KI → I

cuz he is really really short, assuming an unorthodox and inherently unlucky configuration of elevator buttons…

explanation: