Which of the following will have the most negative electron gain enthalpy and which the least negative ? P, S, CI, F.

Which of the following will have the most negative electron gain entha

1.	Which of the following will have the most negative electron gain enthalpy and which the least negative ? P, S, CI, F.
Answer» Solution :Electron gain ENTHALPY generally becomes more negative across a period as we move from left to right. Within a group, electron gain enthalpy becomes less negative down a group. HOWEVER, adding an electron to the 2p-orbital leads to GREATER repulsion than adding an electron to the larger 3p-orbital. Hence the element with most negative electron gain enthalpy is chlorine, the one with the LEAST negative electron gain enthalpy is phosphorus.