The formation of oxide ion `O^(2-)(g)` from oxygen atom requires first an exothermic and then an endothermic step as shown below
`O(g)+e^(-) rarr O^(-)(g), DeltaH^(-) = - 141 kj mol^(-1)`
`O^(-)(g) +e^(-) rarr O^(2-) (g), DeltaH^(-) =+ 780 kj mol^(-1)`
Thus, process of formation of `O^(2-)` in gas phase is unfavourable even through `O^(2-)` is isoelectronic with neon. It is due to the fact that

The formation of the oxide ion O^(2-)(g) , form oxygen atom requires first an exothermic and then an endothermic step as shown below, O(g)+e^(-) to O^(-)(g),DeltaH_(f)^(0)=-141kJ*mol^(-1) O^(-)(g)+e^(-) to O^(2-)(g),DeltaH_(f)^(0)=+780kJ*mol^(-1) ltbr. Thus, process of formations of O^(2-) in gas phase is unfavourable even through O^(2-) is isoelectronic with neon. it is due to the fact that-

The formation of the oixde ion, O^(2+)(g) from oxygen atom requires first an exothermic and then an endothermic step as shown below: O(g)+e^(-) rarr O^(-)(g), Delta H^(O)=-141kJ mol^(-) O(g)+e^(-) rarr O^(-)(g), H^(O)=-kJ mol^(-) Thus the process of formation of O^(2-) in gas phase is neon. It is due to the fact that

The formation of the oxide ion O _((g)) ^(2-) from oxygen atom requires first an exothermic and then an endothermic step as shown below : O _((g)) + e ^(-) to O _((g )) ^(-) ,Delta _(f) H^(0) =-141 kJ mol ^(-1) O _((g)) ^(-) +e ^(-) to O _((g)) ^(-2) ,Delta _(f) H^(0) =+ 780 kJ mol ^(-1) Thus, process of formation of O^(2-) in gas phase is unfavourable even thrugh O ^(2-) is isoelectronic with neon. It is due to the fact that (2015)

The formation of the oxide ion O^2-(g) from oxygen atom requires first an exothermic and then an endothermic step as shown below: O(g)+e^ rarr O^-(g),delta _t H=-1.41kJ mol^-1 , O^-(g)+e^- rarr O^2-(g),delta_t H=+1780 kjmol^-1 thus process of formation of O^2- in gas phase is unfavourable even though O^2- is isoelectronic with neon it is due to the fact that