Question

2) Exblain the trend in general o electron affinity ii) electronegativity of elements in a) on moving from left to right across a peried b) on moving down a group Give me reasons for the change in each periodic trend -​

Answer 1

Answer:

(1) General variations of electron affinity in the Periodic table: Electron affinity, in general, increases with increase in nuclear charge and decreases with increase in atomic size. Variations in a Period: On moving across a period from left to right, atomic size decreases while nuclear charge increases. Both of these factors increase the electron affinity. Thus electron affinity, in general, increases from left to right on moving across a period in the period table. Variation in a Group: On moving down a group from top to bottom, both atomic size and nuclear charge increase. However, the effect of increase in atomic size dominates over the effects of increase in nuclear charge. Thus, electron affinity, in general, decreases from top to bottom on moving down a group in the periodic table. (2) General variations of electronegativity in the periodic table: Electronegativity increases with increase in nuclear charge and decreases with increase in atomic size. Variations in a Period : On moving across a period from left to right atomic size decreases while nuclear charge increases. Both of these factors increase the electronegativity. Thus electronegativity, in general, increases from left to right on moving across a period in the periodic table. Variations in a Group: On moving down a group from top to bottom both atomic size and nuclear charge increase. However, the effect of increase in atomic size dominates over the effect of increase in nuclear charge. Thus electronegativity, in general, decreases from top to bottom on moving down a group in the periodic table.