Question

Why does the reactivity of metals increase and that of non-metals decrease as we move down the group ?

Answer 1

Hint: The incentive for a chemical substance to undertake a chemical reaction, either by itself or with other materials, with an overall release of energy is referred to as reactivity in chemistry. The rate at which a chemical material tends to undergo a chemical reaction over time is referred to as reactivity. The physical characteristics of the sample control reactivity in pure chemicals. Grinding a sample to a larger specific surface area, for example, improves its reactivity.

Complete answer:
The amount of reactivity of a metal is defined by its metallic character. Metals have low ionisation energies, which indicates that they lose electrons in chemical processes. Metal atoms have a low electronegativity, which indicates that they have a low attraction for electrons inside a complex. The most reactive metals would be found in the lower left section of the periodic table, according to the trend summary. Cesium, which is not found in nature as a free element, is the most reactive metal. It reacts explosively with water and will spontaneously ignite in the presence of air. In the alkali metal group, francium lies below cesium, but it is so uncommon that most of its characteristics have never been seen.
As you progress through the groups, the metallic aspect becomes more prominent. Because the ionisation energy drops as you go down a group (and increases as you go up a group), metals lower in the group have a greater capacity to lose electrons, making them more reactive. Furthermore, when one moves down a group, the atomic radius rises, pushing the outside electrons further away from the nucleus and making that electron less attracted to the nucleus.
Nonmetals have a strong affinity for electrons inside a compound and tend to acquire electrons in chemical processes. The most reactive nonmetals are found in the periodic table's top right corner.
The element fluorine is the most reactive nonmetal because noble gases constitute a unique category due to their lack of reactivity. It does not exist as a free element in nature. Fluorine gas interacts explosively with a variety of other elements and compounds, making it one of the most hazardous chemicals known.

Note:
It's worth noting that the distinction between metallic and non-metallic character is hazy. As we progress down the periodic table, the tendency to absorb electrons (non-metallic) increases while the likelihood of an atom giving up one or more electrons decreases.