Atomic Structure and Periodic Trends
Unit 1: Introduction to Atomic Theory
Learning Objectives: Understand the historical development and fundamental concepts of atomic theory.
Topics:
Early models of the atom
Democritus and the idea of atoms
Dalton’s Atomic Theory
Discovery of subatomic particles
Electron: Cathode ray experiments (J.J. Thomson)
Proton: Goldstein and Rutherford
Neutron: Chadwick’s discovery
Rutherford’s gold foil experiment and the nuclear model
Bohr’s model of the hydrogen atom
Quantized energy levels
Emission spectra and the hydrogen line spectrum
Modern quantum mechanical model
Wave–particle duality (de Broglie, Einstein)
Heisenberg’s uncertainty principle
Schrödinger’s wave equation and orbitals
Unit 2: Atomic Structure and Electron Configuration
Learning Objectives: Describe the arrangement of electrons and their influence on chemical behavior.
Topics:
Quantum numbers and their significance
Principal , azimuthal (l), magnetic (mₗ), and spin (mₛ) quantum numbers
Atomic orbitals and shapes (s, p, d, f)
Aufbau principle, Pauli exclusion principle, Hund’s rule
Writing electron configurations
Standard notation and noble gas shorthand
Electron configuration of ions
Orbital diagrams and stability (half-filled and fully filled subshells)
Unit 3: The Periodic Table and Periodic Trends
Learning Objectives: Relate atomic structure to the organization and trends of the periodic table.
Topics:
Development of the periodic table
Mendeleev’s arrangement and prediction of elements
Modern periodic law (atomic number basis)
Classification of elements
Groups, periods, and blocks (s, p, d, f)
Metals, nonmetals, and metalloids
Periodic trends and explanations based on atomic structure
Atomic radius (and ionic radius)
Ionization energy
Electron affinity
Electronegativity
Shielding effect and effective nuclear charge
Exceptions and anomalies in trends
Unit 4: Applications and Problem Solving
Learning Objectives: Apply periodic trends and atomic structure to predict and explain chemical behavior.
Topics:
Predicting reactivity using periodic trends
Metallic and nonmetallic character
Formation of ions and ionic bonding tendencies
Periodicity in chemical and physical properties
Practice problems and case studies
Unit 5: Review and Assessment
Learning Objectives: Synthesize understanding through review and application.
Activities:
Concept maps linking atomic structure to periodic properties
Group ac
tivities and lab experiments (e.g., flame tests, spectral analysis)
Quiz/test on atomic theory and periodic trends
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