(N/A) Atomic hydrogen is highly unstable and hence it is very reactive. Its electronic configuration is $1s^1$. For stability,it tends to complete its shell by gaining,losing,or sharing an electron,making it highly reactive towards almost all elements.
Atomic hydrogen forms hydrides in three ways:
$(i)$ By losing one electron to form $H^+$.
$(ii)$ By gaining one electron to form $H^-$.
$(iii)$ By sharing one electron to form a covalent bond.
In contrast,molecular hydrogen $(H_2)$ has a very high bond dissociation energy of $435.88 \ kJ \ mol^{-1}$. As a result,the $H-H$ bond is strong and stable,making molecular hydrogen relatively inert at room temperature,reacting only with a few elements.