Question
Explain giving various reasons for the variation of electronegativity along a period and along a group.
Solution
(i) Variation of electronegativity in a period: In a period electronegativity increases in moving from left to right. This is due to the reason that nuclear charge increases whereas atomic radius decreases as we move from left to right in a period. Halogens have the highest value of electronegativity in their respective period.
(ii) Variation of electronegativity in a group: In a group, electronegativity decreases on moving down the group. This is due to the effect of increased atomic radius. For example among halogens, fluorine has the highest electronegativity.
