Question

Which one of the following elements is most reactive?
A) Fluorine
B) Argon
C) Helium
D) Radon

Answer 1

Hint: As we know that in the periodic table totally $118$ elements are present now. In the periodic table there are eighteen groups and seven periods. In the periodic table the seventeenth group is the halogen group. In this group, four elements are only considered as halogen out of five elements in the column. There are fluorine, chlorine, bromine and iodine considered as halogen in the modern periodic table. The symbols of fluorine, chlorine, bromine and iodine are \[{\text{f,Cl}}{\text{.BrandI}}\] respectively.

Complete answer:
The given list of elements are Fluorine, argon, helium and radon.
Out of these four elements, fluorine is the most reactive element.
Because fluorine is one of the halogens in the periodic table. Fluorine reactivity is due to the electron affinity. The electron affinity of fluorine is high. Fluorine wants one electron for the stable electronic configuration.
According to the above discussion, we conclude fluorine is the most reactive element.

So, the correct answer is “Option A”.

Note:
We need to remember that the halogen is the most electron affinity group in the periodic table. Halogen is also the most electronegativity group in the periodic table. The ionisation energy of the halogen is very less compared to other groups. In halogen from top to bottom, electron affinity decreases. Chlorine is the highest electron affinity species in the periodic table, because the size of the fluorine is very small compared to chlorine. But, the electronegativity value of fluorine is high compared to the electronegativity value of chlorine. The symbol of \[X\] is used for an element; there are fluorine, chlorine, iodine and bromine in the chemical reaction.