hydrogen - Why is the H-H Bond Dissociation Enthalpy so high?

"The H-H Bond Dissociation Enthalpy is the highest for a single bond between 2 atoms of any element."

Answer

The bond dissociation enthalpy is the energy needed to break one mole of the bond to give separated atoms - everything being in the gas state.

For covalent bonds, bond energies and bondlengths depend on many factors:

• electron afinities,


• sizes of atoms involved in the bond,


• differences in their electronegativity,



• and the overall structure of the molecule.

There is a general trend in that the shorter the bondlength, the higher the bond energy.

Hydrogen has a relatively small atom and short bondlength hence very strong strong attractions between the atoms which will consenquently increase its bond dissociation ethalpy.

Credits

1. 
   

   Bond enthalpy (Bond energy)

   
   


2. 
   
   

   Inorganic chemistry bond enthalpy of Hydrogen]2