Question

Question 3.22 What is the basic difference between the terms electron gain enthalpy and electronegativity?

Class XI Classification of Elements and Periodicity in Properties Page 93

Answer 1

electron gain enthalpy : electron gain enthalpy is the amount of energy released when we add an electron to an isolated gaseous atom in ground state. it is measurable quantity and also it has special unit { KJ/mol }
$e.g., X(g) +e^------->X^-(g) + Q$
Here, Q is electron gain enthalpy of element X.
$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: but$
electronegativity : it is the tendency of an atom of an element to attract the shared pair of electrons towards itself in a covalent bond . it is unit and dimensionless quantity .
$A^{\delta+}-------ee--B^{\delta-}$
here , you can see that B is more electronegative than A because B attract shared pair of electrons towards itself.