Ionization Enthalpy

Ionization Enthalpy

Every Group 14 element has a higher first ionisation enthalpy than the corresponding Group 13 element — a direct consequence of Group 14's smaller atomic size and extra nuclear charge for a comparable shell structure.

Down Group 14, ionisation enthalpy generally decreases, but not smoothly:

• The fall from Si → Ge → Sn is quite small.
• Going from Sn → Pb, ionisation enthalpy actually rises slightly instead of continuing to fall. …