Why is the electron affinity of lead (Pb) much higher than the expectation based on the group trend?
1
The unique electronic configuration of Pb allows for a more favorable stabilization of the added electron, resulting in a higher electron affinity compared to other group members.
2
Lead exhibits significant relativistic effects due to its high atomic number, which enhances the effective nuclear charge felt by the incoming electron, leading to increased electron affinity.
3
The presence of filled d-orbitals in lead stabilizes the added electron, which reduces electron-electron repulsion, thus resulting in a higher electron affinity than expected for its group.
4
The higher ionization energy of lead compared to its group members increases the electron affinity, as the energy released upon electron gain is significantly greater due to stronger nuclear attraction.