Among the following number of elements having bond dissociation energy greater than ${\mathrm{F}}_2$ are:

${\mathrm{Cl}}_2,{\mathrm{Br}}_2,{\mathrm{I}}_2,{\mathrm{N}}_2,{\mathrm{O}}_2,\mathrm{CO}$

The bond dissociation energy is the energy which is needed o break a bond and form two atomic or molecular fragments.

The elements having bond dissociation energy greater than ${\mathrm{F}}_2$ are

${\mathrm{Cl}}_2,{\mathrm{Br}}_2,{\mathrm{N}}_2,{\mathrm{O}}_2,\mathrm{CO}$

Thus, the correct answer is 5.