How does #"electron gain enthalpy"# evolve with respect to the Periodic Table?

1 Answer
Sep 11, 2017

Well, #"electron gain enthalpy"#, is I presume electron affinity.

Explanation:

And #"electron affinity"# is AN ATOMIC phenomenon.....And by definition this is the enthalpy change involved in the formation of #1*mol# of gaseous anions from #1*mol# of gaseous atoms, and #1*mol# of electrons......

#M(g) + e^(-) rarr M^(-)(g) + Delta#

Elements with high nuclear charge, i.e from the right hand side of the Periodic Table as we face it, tend to have high electron affinities (i.e. highly negative, because the reaction as written is exothermic).

And electronegativity, is conceived to be the tendency of an atom involved in a chemical bond to polarize electron density towards itself. There are various scales, of which the Pauling scale was the earliest, and still most widely used.

And thus #"electronegativity"# is a property of atoms in molecules; whereas #"electron affinity"# is a fundamental, directly measurable property of atoms.

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