37) Give reasons why elements of group VIIA in the periodic table are very reactive.
38) Give reason for decreasing reactivity of elements as we go down the group.
39) Give reason why elements of group VA in the periodic table are very reactive.
40) Give reason for increasing reactivity of elements as we go down the group IA.
41) What is the reason for the fact that reactivity of group 'V' element decreases as we go down the group?
Answer (1)
Sure! Let's explore the reactivity trends of elements in the periodic table, focusing on groups VIIA (Group 17), VA (Group 15), and IA (Group 1).
Reactivity of Group VIIA Elements (Halogens):
Elements in Group VIIA, also known as halogens, are very reactive because they have seven electrons in their outermost shell and need only one more electron to achieve a stable electron configuration, similar to noble gases.
This high electronegativity makes halogens very eager to gain electrons, especially from other elements, to complete their octet and achieve stability. This eagerness to gain electrons contributes to their high reactivity.
Decreasing Reactivity Down the Group VIIA:
As we move down Group VIIA, the reactivity decreases. This is because larger atoms have more electron shells, increasing the distance between the nucleus and the outermost electrons.
The increased distance and additional electron shielding reduce the effective nuclear attraction for incoming electrons, making heavier halogens like iodine less reactive than lighter ones like fluorine.
Reactivity of Group VA Elements:
Group VA elements (Group 15) have five valence electrons. They are reactive but not as much as halogens. Their reactivity is due to their tendency to gain three electrons to complete their octet or form covalent bonds with other nonmetals.
Nitrogen, for example, is very reactive in certain conditions and can form a variety of compounds, owing to its ability to gain or share electrons.
Increasing Reactivity Down Group IA Elements (Alkali Metals):
Reactivity in Group IA, or alkali metals, increases as we move down the group. This can be attributed to the increasing atomic size and the decreasing ionization energy.
As the atoms become larger, the single valence electron is further from the nucleus and more easily lost, making elements like cesium more reactive than lithium. The lower ionization energy facilitates the loss of this electron.
Decreasing Reactivity Down Group V Elements:
In group V (Group 15), the reactivity decreases down the group because the elements become larger, with more shielding between the outer electrons and the nucleus.
This makes it more challenging for the elements to gain three electrons to complete their octet, reducing their reactivity.
These trends are important for understanding how elements interact and form compounds. By examining group trends, we can predict and explain the behavior of elements in chemical reactions.
