The electronic contigurations of four elements are given below. Arrange these elements in the correct order of magnitude of their electron affinity(i) 2 s22p5(ii) 3 s23p5(iii) 2 s22p4(iv) 3 s23p4

Electron affinity generally increases across a period and decreases down a group in the periodic table. This is because as we move across a period, the atomic radius decreases, so the nucleus can attract the incoming electron more strongly. On the other hand, as we move down a group, the atomic radius increases, so the nucleus has less attraction for the incoming electron.

Given the electronic configurations:

(i) 2s22p5 - This is the configuration for Fluorine (F) (ii) 3s23p5 - This is the configuration for Chlorine (Cl) (iii) 2s22p4 - This is the configuration for Oxygen (O) (iv) 3s23p4 - This is the configuration for Sulfur (S)

The order of electron affinity (from highest to lowest) would be:

F > Cl > O > S

This is because Fluorine is in the same period as Oxygen but to the right, so it has a higher electron affinity. Chlorine is below Fluorine in the same group, so it has a lower electron affinity. Oxygen is to the left of Fluorine in the same period, so it has a lower electron affinity. Sulfur is below Oxygen in the same group, so it has the lowest electron affinity.