A simplified application of $\mathrm{MO}$theory to the hypothetical 'molecule' $\mathrm{OF}$ would give its bond order as:

$\mathrm{O}=$  Each oxygen atom has $2 + 6= 8$ electrons

$\mathrm{F}$ $=$Each oxygen atom has 2+7= 9 electrons

$\mathrm{O}=\sigma 1{\mathrm{s}}^2\sigma 1{\mathrm{s}}^2\sigma 2{\mathrm{s}}^2\sigma 2\mathrm{s}\sigma 2{\mathrm{p}}^2\mathrm{x}\left\{\begin{array}{c}\pi 2\mathrm{py}\\ \pi 2{\mathrm{pzz}}^1\end{array}\right.$

$\mathrm{F}==\sigma 1{\mathrm{s}}^2\sigma 1{\mathrm{s}}^2\sigma 2{\mathrm{s}}^2\sigma 2{\mathrm{s}}^2\sigma 2{\mathrm{px}}^2\left\{\begin{array}{l}\pi 2{\mathrm{py}}^2\\ \pi 2{\mathrm{pzz}}^1\end{array}\right.$

$\mathrm{Bond} \mathrm{order} =\frac{( \mathrm{No}.\mathrm{of} \mathrm{bonding} – \mathrm{No}.\mathrm{of} \mathrm{anti}-\mathrm{bonding} )}{2}$

$=\frac{(10-7)}{2}$

$=\frac{3}{2}=1.5$