Dihydrogen under certain reaction conditions combines with all elements except noble gases. This is mainly because the atoms of these elements already have a full valence shell. What it means is that there is no instability and therefore they do not have any tendency to lose, gain, or share electrons and form bonds with other elements.
Non-reactivity of noble gases
The noble gases do not react under normal conditions. The non-reactivity of noble gases is due to the following reasons
- The valence shell of the noble gases is completely filled. The next available shell is of much higher energy.
- Noble gases have very high ionization enthalpies
- They have large positive values of electron gain enthalpy.
Noble gases have no tendency to gain or lose electrons under ordinary conditions. This is the only reason due to which they do not compete in chemical reactions and remain inert. According to modern researchers, it has been seen that noble gases can be compelled to take part in a chemical reaction under certain specific conditions.