Which group in the periodic table consists mainly of reactive elements?

The correct answer indicates that alkali metals primarily consist of reactive elements due to their unique position in the periodic table and their electronic configuration. Alkali metals, which are found in Group 1, have a single electron in their outermost shell. This configuration makes them highly eager to lose that one electron in order to achieve a stable electronic arrangement, akin to that of the nearest noble gas.

As a result, alkali metals react vigorously with water and halogens, and their reactivity increases as you move down the group from lithium to cesium. This propensity for reaction is a hallmark of alkali metals, making them some of the most reactive elements in the periodic table.

In contrast, noble gases are characterized by their full outer electron shells, which makes them very stable and largely unreactive. Alkaline earth metals, while also reactive, do not reach the same levels of reactivity as alkali metals, and transition metals, while they can participate in various chemical reactions, do not exhibit the same level of reactivity as alkali metals in general.