Electron gain enthalpy values

Electron gain enthalpy value for oxygen is negative ( -1 42 kJ mol e^(-1)) while sum of electron gain enthaplies of O and (O^(-)) respectively si positive is (702kJ "mol"^(-1)) .Explain the reason for opposite sign for two values . Also calcularte EA_2 value .

Electron-gain enthalpy value of Cu is negative while that of Zn is positive explain?

Which of the following noble gases has the highest positive electron gain enthalpy value ?

Name a halogen which has more negative electron gain enthalpy value?

The absolute value of the electron gain enthalpy of halogens satisfies :

Electron gain enthalpy is an important periodic property. a) What is meant by electron gain enthalpy? b) What are the factors affecting electron gain enthalpy? c) How electron gain enthalpy varies on moving across a period? Justify.

The negative value of electron gain enthalpy is less for fluorine than for chlorine . Why?