Question

The formation of f-(g) from f(g) is exothermic whereas that of o2-(g) from o(g) is endothermic. explain.

Answer 1

Beacause durning the formation of f-(g) there is a liberationof enegy and durning the formation of O2(g) there is an absorption of heat .

Answer 2

Fluorine is smallest element in periodic table.Addition of electron causes a strong repulsion between 2P electrons. Hence a large amount heat is evolved during this process where as in case of oxygen there is 6 electrons that is 4 electrons are in 2P orbital. On addition of 2 electron O2 will get stable fulfilled P6 configuration. In this process a large amount of heat is absorbed. Thats why the formation of f-(g) from f(g) is exothermic whereas that of o2-(g) from o(g) is endothermic.