Question

Which of the following halogens doesn't exhibit a positive oxidation state in its compounds?
A. CI
B. Br
C. I
D. F

Answer 1

Hint: To answer this question the periodic properties of the elements from different groups should be known. The periodic properties have opposite trends between left to right and top to bottom. Halogens are from group 17. Which is on the right side of the periodic table.

Complete step by step answer:
Halogens are the most electronegative atoms of each period of the periodic table. Top to bottom of the halogen group size increases because of the number of electrons as well as the number of shells increases. Now with increasing the number of shells their atomic mass is also increasing. Due to the high atomic mass of the bottom elements of this group, the physical state of the bottom elements is solid at room temperature. And due to low molecular mass top elements are in a gaseous state at room temperature.
Now the top elements of this group are Fluorine, chlorine. And bottom elements are Astatine and Iodine
From top to bottom electronegativity decreases and electropositivity increases. Due to this reason, the positive oxidation state formation tendency is greater in bottom elements.
Due to this reason, the highest electronegative elements fluorine does not exhibit a positive oxidation state.

So, the correct answer is D.

Note:
Due to the high atomic mass of the bottom elements of this group, the physical state of the bottom elements is solid at room temperature. And due to low molecular mass top elements are in a gaseous state at room temperature. But bromine is in the middle of the group and also the molecular mass of from is not large to be solid as well as low to be gas. Due to this reason, the physical state of bromine is liquid at room temperature.