Question

The order of increasing polarisability of the halide ions is


A) F-, Cl-, Br-, I-

B) I-, Br-, Cl-, F-

C) Cl-, Br-, I-, F-

D) F-, I-, Br-, Cl- and why?

Answer 1

I think answer will be A because electronegativity of elements always decrease down the group in the periodic table

Answer 2

Answer:

 (A) F -, Cl-, Br-, I.

Solution:

Polarisability is the ability of displacement of electrons of an atom from equilibrium by a nearby electric field. Negatively charged ions like halogens which include F, I, Br, Cl are highly polarizable and those with positively charged ions like metals have low polarisability. Generally, polarisability increases down the group of elements in the periodic table because the atomic size increases which make the larger electron clouds to distort easily. Fluorine is with least polarisability because it has smaller atoms, whereas iodine with larger atomic clouds has more polarisability.