The incomplete data table below lists electron affinities for the third-period…
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
The incomplete data table below lists electron affinities for the third-period p-block elements.
Element Al Si P S Cl Ar
EA (kJ mol⁻¹) −43 −120 _____ −200 −349 +96
Analyze the trend and complete the table.
(a) Predict a numerical value (including sign) for the EA of P that is consistent with both the given trend and known anomalies in electron affinity data.
(b) Justify your predicted value by discussing subshell electron configurations, effective nuclear charge, and electron–electron repulsion within the 3p subshell.
(c) On a qualitative sketch of EA versus atomic number for Al through Ar (no actual drawing required), describe the shape of the curve and identify the major discontinuities. Explain the chemical origin of each discontinuity.