Explain variations in electron gain enthalpy and electronegativity of group-16 elements.

Explanation

(i) Electron gain enthalpy : Group-16 elements have high electron gain enthalpy. Oxygen has less negative electron gain enthalpy because of the compact nature (Small size) of oxygen atom.
However, from sulphur onwards, the electron gain enthalpy becomes less negative upto polonium.
Order of electron gain enthalpy:
`O lt S gt Se gt Te gt Po`
(ii) Electronegativity : Oxygen is the second most electronegative element after fluorine. Down the group, the electronegativity decreases with increase in atomic number. This implies that metallic character increases from oxygen to polonium.