For which of the following process, the value of electron gain enthalpy is positive ?

Options

A. `F(g)+erarrF^(-)(g)`
B. `Cl(g)+e^(-)rarrCl(g)`
C. `Be(g)+e^(-)rarrBe^(-)(g)`
D. `B(g)+erarrB^(-)(g)`

Answer

3

Explanation

Be has stable configuration `1s^(2)2s^(2):` so addition of electron will require energy and thus the value of electron gain enthalpy will be positive.