As we known that .half filled atom are stable. But in the case of H (hydrogen) it is not stable .even it is half filled. ?
First being clear to the concept of half filled orbitals' stability.. it is due to the fact that half filled configuration helps an orbital to maintain its degeneracy by maintaing equal energy inspite of getting full filled configuration. But in case of hydrogen. No degeneracy is required and there is only one orbital