Arrange the following metals in the decreasing order of their reactivity.
Metals are arranged in the decreasing order of their reactivities, and this table is known as the reactivity series.
K and Na react the most vigorously with water, reacting violently even with cold water to release H2 gas, followed by Ca, which reacts with cold water, but with less vigour.
Mg barely reacts with cold water, but reacts with warm water.
Fe reacts only with steam.
This trend points to a following order of reactivity -