Which of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for C, Ca, Al, F, O?
Ca < Al < C < O < F
Al < Ca < O < C < F
Al < O < C < Ca < F
C < F < O < Al < Ca
As learnt in
Variation of electron gain enthalpy in periodic table -
-
Electron gain enthalpy increases along the period as the attraction between incoming electron and the nucleus increases.
Also, it decreases down the group due to increased atomic size.
Increasing order of electron gain enthalpy:
Ca < Al < C < O < F
Option 1)
Ca < Al < C < O < F
This option is correct
Option 2)
Al < Ca < O < C < F
This option is incorrect
Option 3)
Al < O < C < Ca < F
This option is incorrect
Option 4)
C < F < O < Al < Ca
This option is incorrect