#"the atomization energy is the energy associated with the "#
#"formation of 1 mole of gaseous atoms from 1 mole of gaseous"#
#"element in its standard state under standard conditions......"#
#"and the bond dissociation energy is the energy associated with"# #"the CLEAVAGE of 1 mole of gaseous bonds from 1 mole of"#
#"gaseous molecules to form 2 gaseous radicals........."#
So there are our definitions; let's see if we can represent each process by an equation, using a bimolecular species, #X_2#, as our exemplar:
#"ATOMIZATION:"#
#1/2X_2(g) + "E"_1rarr dotX(g)#
#DeltaE_1="something"#
#"DISSOCIATION:"#
#X-X(g) + "E"_2rarr 2dotX(g)#
#DeltaE_2="some other thing"#
So given the definition, if we have a homonuclear diatomic, i.e. dihydrogen, dihalogen, etc, then #DeltaE_2=2xxDeltaE_1#. That is the #"energy of atomization"# is HALF the #"bond dissociation energy"# for gaseous homonuclear diatomic molecules.