Question

F, cl nd br are the elements each having seven valence electrons. which is more reactive..justify

Answer 1

bromine has the largest atomic size (as atomic size increases down a group) as a result it's capacity to hold electrons is also reduces. so it would lose electrons more easily than F or Cl. so Br is more reactive.

Answer 2

Fluorine is most reactive bcoz the atomic size of fluorine is small as the no. of shells in fluorine is the least. So due to small atomic size it can hold electron easily.
The decreasing reactivity order is
F>Cl> Br > I

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