Question

Which neutral molecule will be isoelectric with $Cl{O}^{-}$?

Answer 1

$Cl{O}^{-}$ is isoelectronic to ClF. Also, both species contain 26 electrons.

Total electrons $Cl{O}^{-}$ = 17 + 8 + 1 = 26

In ClF = 17 + 9 = 26

ClF acts like a Lewis base as it accepts electrons from F to form $Cl{F}_3$.