why atom take part in a chemical reaction insted of molecules as they all are not stable?

As we know that , All the atom other than Noble gases have less than 8 electron in their outermost shells . In other words , the outermost shell of these atom do not have stable electronic configuration ( octate rule) . Therefore they combined with other atom or itself i.e through chemical reaction they attend their stable electronic configuration .

In easy way we can say

Atom take parts in chemical reaction in order to gain it's stable electronic configuration i.e Noble gas electronic configuration.

According to modern view the atom take part in chemical reaction to acquire a state of minimum energy . Because As we known every system in the universe has a natural tendency to attained a state of minimum energy.

The state of minimum energy corresponds to state of maximum stability . For example water always flow down the hill , a hot body radiates energy and cools down .

Similarly it is expected that isolated atom which have high potential energy enters into chemical combination to form molecules with lower potential energy . Hence the atom combines to each other , only if the process leads to lowering of energy . If there is no fall in potential energy of the system no chemical reaction take place .

Regards

Arun (askIITians forum expert)