The order of electron affinity for $F, Cl, Br,$ and $I$ is .....

In which of the following processes is energy absorbed?

When the first electron gain enthalpy $(\Delta _{eg}H)$ of oxygen is $-141 \ kJ/mol,$ its second electron gain enthalpy is

Electron gain enthalpy values $(\Delta_{eg} H)$ (in $kJ \ mol^{-1}$) of elements $X$,$Y$ and $Z$ are $-349$,$-200$ and $-295$ respectively. $X$,$Y$ and $Z$ are respectively

Which of the following is correct for the electron affinity of halogens?

Which of the following ions is most unlikely to exist?