Question

Which of the following elements of the same group have
a. Largest atomic size
b. Highly reactive?
F, Cl, Br
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Answer 1

As we know, in modern periodic table, the size of an element increases down the group and electronegativitydecreases down the group therefore among the above halogens, Br has largest size. The general reactivity of halogens decreases down the group. Fluorine is the most reactive element among halogens because of its small size and the most electronegative nature which make it to accept an electron easily and form a bond with other element. Hence, fluorine is the most reactive element of the group.