1.7 Periodic Trends

Explain the relationship between trends in atomic properties of elements and electronic structure and periodicity.

• The organization of the periodic table is based on patterns of recurring properties of the elements, which are explained by patterns of ground-state electron configurations and the presence of completely or partially filled shells (and subshells) of electrons in atoms.
  • Exclusion: Writing the electron configuration of elements that are exceptions to the aufbau principle will not be assessed on the AP Exam.
• T rends in atomic properties within the periodic table (periodicity) can be predicted by the position of the element on the periodic table and qualitatively understood using Coulomb’s law, the shell model, and the concepts of shielding and effective nuclear charge. These properties include:
  • i. Ionization energy
  • ii. Atomic and ionic radii
  • iii. Electron affinity
  • iv. Electronegativity.
• The periodicity (in