Would you expect the second electron gain enthalpy of oxygen as positive, more negative or less negative than the first? Justify.

Explanation

`2^(nd)` gain enthalpy means energy released when an electron is added to uni negative ion.
`O_((g)) + e^(-) rarr O_((g))^(-) + 141` KJ/mole
`o_((g))^(-) + e^(-) rarrO_((g))^(-(2)) - 780` KJ/mole
`rarr 2^(nd)` gain enthalpy of oxygen is positive because `O^(-)` ion doesnot accept an electron readily and the entering electron have to over come the repulsive force.