Amongst the following, the number of oxide(s) which are paramagnetic in nature is
$N{a}_{2}O,K{O}_2,N{O}_2,N_{2}O,Cl{O}_2,NO,S{O}_2,C{l}_{2}O$

4) Among the given , oxides which are paramagnetic are 
$K{O}_2,N{O}_2,Cl{O}_2,NO$
 $\begin{array}{l}K{O}_2=1+6+6=13\\ N{O}_2=5+6+6=17\end{array}$      
   $\begin{array}{l}Cl{O}_2=7+6+6=19\\ NO=5+6=11\end{array}$   
Among the given oxides which are diamagnetic are 
$N{a}_{2}O,N_{2}O,S{O}_2,C{l}_{2}O.$
$\begin{array}{l}N{a}_{2}O=1+1+6=8\\ N_{2}O=5+5+6=16\\ S{O}_2=6+6+6=18\\ C{l}_{2}O=7+7+6=20\end{array}$   
There are total four oxides which are paramagnetic in nature .