Question

Increasing order of electron gain enthalpy of the group $16$ is:

Answer 1

Electron gain enthalpy order:

• Electron gain enthalpy is defined as the amount of energy released when an electron is added to an isolated gaseous atom.
• As the size of the atom increases, the electron gain enthalpy decreases, and thus the electron gain enthalpies of the chalcogens decrease down the group.
• But exceptionally, sulphur is known to have a higher negative electron gain enthalpy compared to oxygen, which is due to the smaller structure of oxygen, which contributes to the interelectronic repulsion between valence electrons and any other electrons that approach.
• Hence, the increasing order of electron gain enthalpy of group 16 is given as:

$\mathrm{S}<\mathrm{O}<\mathrm{Se}<\mathrm{Te}$

Hence, the increasing order of electron gain enthalpy of group 16 is: $\mathrm{S}<\mathrm{O}<\mathrm{Se}<\mathrm{Te}$.