Amongst the following, the number of oxide(s) which are paramagnetic in nature is: \(\mathrm{Na_2O},\ \mathrm{KO_2},\ \mathrm{NO_2},\ \mathrm{N_2O},\ \mathrm{ClO_2},\ \mathrm{NO},\ \mathrm{SO_2},\ \mathrm{Cl_2O}\)