Question

Which is the correct increasing order of electronegativity of halides?
A. F, Cl, Br, I
B. I, Br, Cl, F
C. Br, Cl, F, I
D. Cl, Br, I, F

Answer 1

Hint: We know that an atom's property to accept electron(s) to complete its octet in the gaseous state is termed electronegativity. Noble gases namely Helium, Argon, Xenon, etc. have fully filled valence shells, therefore, they have electronegativity of zero, which means they do not accept any electron.

Complete Step by Step Solution:
Let's discuss the trend of electronegativity down a group of the periodic table. As we know that when we go down the group, there is a decrease in electronegativity because of the increase in the size of the atom. As the increase in size occurs, the distance between the nucleus and the valence shell electrons increases and thus the electrons are able to attract shared pairs towards themselves.

We know, Fluorine belongs to the 2nd period, Chlorine belongs to the 3rd period, Bromine belongs to the 4th period and Iodine is in the 5th period. So, if we follow the trend of decrease of electronegativity down the group, Fluorine has the highest electronegative character and Iodine is the least electronegative atom.

Hence, the correct order of halides in terms of increasing electronegativity is, I, Br, Cl, F, that is, option B.

Note: It is to be noted that halogens such as Fluorine, Bromine, Iodine, Chlorine, etc. are present in group 17 of the modern periodic table. They possess the valency of -1 which means, they accept one electron to acquire stability.