Which amongst the following is incorrect statement?
The bond orders of O$_2^ + $, O2, O$_2^ - $ and O$_2^ {2-} $ are 2.5, 2, 1.5 and 1, respectively
C2 molecule has four electrons in its two degenerate $\pi$ molecular orbitals
H$_2^ + $ ion has one electron
O$_2^ + $ ion is diamagnetic
