Kossel–Lewis Approach

Among all elements Noble Gases are chemically inert i.e. they does not react with any other element nor among themselves. G. N. Lewis and Kossel studied the electronic configuration of noble gases and observed that the inertness of noble gases is due to their complete octet or duplet in case of Helium which has 2 electrons in its last shell. Hence they suggested that they have stable electronic configuration. On the other hand all other elements have incomplete outermost shell and hence have a tendency to attain the stable electronic configuration. They do so by combining with other elements and hence are reactive. Thus, G. N. Lewis and Kossel gave a generalization which states, "the atoms of different elements combine with each other in order to complete their octets or duplets ( in case of H, Li and Be ) to attain stable electronic configuration".