Question

Which of the following elements has the least non-metallic character?
A.Fluorine
B.Chlorine
C.Bromine
D.Iodine

Answer 1

Non-metals mostly consist of p-block elements. They are mostly electron deficient and form anions after addition of extra electrons in their outermost shell. The tendency to accept electrons is called non-metallic character. It decreases with decrease in nuclear attraction between the nucleus and the outermost electrons.

Complete step by step answer:
Non-metals are the elements which have the tendency to accept electrons and form anions. The more will be the attraction of the nucleus with the outermost electrons, the more easily they can gain new electrons. Going down the group, atomic size increases as new shells are added. The outermost shells experience less nuclear attraction due to the shielding effect of the other shells and thus, they can lose electrons easily. This means that going down a group metallic character increases or non-metallic character decreases.
In the case of halogens, we know that fluorine is the most electronegative element. This means that it has a small size and high nuclear attraction, so it can easily accept extra electrons and gain stable configuration. As we go down the group, the electronegativity decreases and the tendency to lose electrons increases. This is because the nuclear attraction between the nucleus and outer electrons decreases. So, iodine will have the least non-metallic character and the most metallic character in group 17.

$\therefore$ The correct option is option D, i.e. Iodine.

Note:
As we move across the period, there is an increase in nuclear charge and decrease in atomic size. Hence, the ability to gain electrons also increases as one goes from left to right in the period. Some other characteristics of nonmetals are: high electronegativity, poor conductivity, brittle and non-lustrous.