Question

what is electron affinity ?Among halogen, Cl has the highest electron affinity value .give reasons.​

Answer 1

Answer:

Electron Affinity is a trend in the modern periodic table.

Electron Affinity (EA) is the amount of energy released when a neutrally isolated gaseous atom is converted into negatively charged anion by the addition of one electron.

It is measured in eV/atom and it's SI unit is kJ/mole.

General Formula:

$\red{M + e- --> M- + EA}$

M is any element.

Generally electron affinity decreases as one goes down in the periodic table, however Chlorine has greater EA than Fluorine and Sulphur has greater EA than Oxygen.

Reason:

Fluorine and Oxygen have a very small atomic size as a result of which the incoming electron does not receive much attraction as there is a force of repulsion from neighbouring electrons.

Hope this helps you.