Why does group 15 elements have greater ionization enthalpy than group 16 elements?

The correct answer is They have extra stable half-filled p orbital.

Key Points

• Group 15 elements have a half-filled p orbital configuration, which is extra stable due to symmetrical distribution of electrons.
• Stability of half-filled orbitals increases the ionization enthalpy because more energy is required to remove an electron from a stable configuration.
• In contrast, group 16 elements have one additional electron in the p orbital, leading to electron repulsion and lesser stability.
• The extra stability of half-filled p orbitals in group 15 elements makes it more difficult to ionize them compared to group 16 elements.

Additional Information

• Ionization Enthalpy:
  • It is the energy required to remove an electron from a gaseous atom or ion.
  • Higher ionization enthalpy indicates a stronger hold of the nucleus on the electrons.
• Electron Configuration:
  • Group 15 elements: ns²np³ configuration.
  • Group 16 elements: ns²np⁴ configuration.
• Stability of Half-filled Orbitals:
  • Half-filled orbitals are more stable due to symmetrical distribution and exchange energy.
  • This stability results in higher ionization enthalpy.
• Nuclear Attraction:
  • The attraction between nucleus and electrons impacts ionization enthalpy.
  • Higher attraction generally leads to higher ionization enthalpy.