Which of the following has the highest electron affinity $(EA)$?

Consider the following conversions:
$(i) \ O_{(g)} + e^- \to O^{-}_{(g)} ; \Delta H_1$
$(ii) \ F_{(g)} + e^- \to F^{-}_{(g)} ; \Delta H_2$
$(iii) \ Cl_{(g)} + e^- \to Cl^{-}_{(g)} ; \Delta H_3$
$(iv) \ Na_{(g)} \to Na^{+}_{(g)} + e^- ; \Delta H_4$
Which of the following statements is incorrect?

The formation of the oxide ion $O_{(g)}^{2-}$ requires first an exothermic and then an endothermic step as shown below. This is because
$O_{(g)} + e^{-} \rightarrow O_{(g)}^{-}; \Delta H^{o} = -142 \ kJ \ mol^{-1}$
$O_{(g)}^{-} + e^{-} \rightarrow O_{(g)}^{2-}; \Delta H^{o} = 844 \ kJ \ mol^{-1}$

The correct order of electron gain enthalpies of $Cl$,$F$,$Te$,and $Po$ is .....

If the electron affinity of an element $M$ is $x \ kJ/mol$,then the ionisation potential of this element is:

Given below are two statements:
Statement $I$: Fluorine has most negative electron gain enthalpy in its group.
Statement $II$: Oxygen has least negative electron gain enthalpy in its group.
In the light of the above statements,choose the most appropriate from the options given below.