Among the following species$N _{2}, N _{2}^{+}, N _{2}^{-}, N _{2}{ }^{2-}, O _{2}, O _{2}{ }^{+}, O _{2}^{-}, O _{2}{ }^{2-}$ the number of species showing diamagnetism is.
$4$
$1$
$2$
$3$
Atomic number of an element is $26.$ The element shows
Which of the following species contain only $\pi \,-\,$ bond but exhibit paramagnetic nature ?
Identify a molecule which does not exist.
$O_2^{2 - }$is the symbol of .. ion
Choose correct order