Chapter 3 (1)

Ask, Seek, Knock

  • Verse: Matthew 7: 7-8

    • "Ask and it will be given to you; seek and you will find; knock and the door will be opened to you."

Chapter 3: Atomic Structure

  • Instructor: Aiye Liang, PhD, Charleston Southern University

Main Topics

  1. Experiments in atomic structure development

    • Crooke

    • Thomson

    • Goldstein

    • Millikan

    • Rutherford

  2. Discovery and types of radioactivity

  3. Atomic structure and the Bohr Model

  4. Electron configuration

  5. Periodic Table

Learning Objectives

  • Explain electrical properties of atoms (3.1)

  • Describe atom structure (3.1)

  • Discuss experiments leading to X-ray discovery and radioactivity (3.2)

  • Distinguish between alpha, beta, and gamma radioactivity (3.3)

  • Sketch nuclear model of the atom (3.4)

  • List particles in the atomic nucleus with masses and charges (3.5)

  • Identify elements and isotopes (3.5)

  • Define quantum (3.6)

  • Arrange electron shells (3.6)

  • Relate quantum energy to orbitals (3.7)

  • Write electron configurations in subshell notation (3.7)

  • Explain relation of electron configuration to periodic table positioning (3.8)

Importance of Atomic Structure

  • Arrangement of atomic parts determines matter properties.

  • Knowledge of atomic combinations allows for synthesis of materials.

  • Understanding atomic structure is essential for health and medical diagnoses.

Electricity and the Atom

  • Electrolyte: Compounds conducting electricity when molten or dissolved.

  • Electrodes: Carbon/metallic rods conducting electrical current.

Ion Definitions

  • Ion: Charged atom or group of atoms.

    • Anion: Negative ion, moves to anode.

    • Cation: Positive ion, moves to cathode.

Key Experiments

  • Cathode Ray Tubes:

    • Crookes discovered cathode rays traveled in straight lines, deflected by electric/magnetic fields.

  • Thomson Experiment (1897):

    • Discovered electrons and their mass-to-charge ratio.

  • Goldstein’s Experiment (1886):

    • Discovered positive rays from perforated cathodes.

  • Millikan’s Oil-Drop Experiment (1909):

    • Measured charge of electron (9.1 × 10^-28 g).

X-Rays

  • Discovered by Wilhelm Rontgen (1895).

  • X-rays: Forms of electromagnetic radiation, widely used in medical diagnostics.

Radioactivity

  • Discovered by Antoine Becquerel (1895); characterized by Marie and Pierre Curie.

  • Spontaneous emission of radiation from certain elements, leading to discovery of polonium and radium.

Rutherford Gold Foil Experiment

  • Discovered atomic nucleus; majority of particles passed through foil, while some deflected sharply.

  • Proposed that most of atomic mass is concentrated in nucleus which contains protons and neutrons.

Isotopes

  • Atoms of the same element differing in neutron count.

  • Most elements exist in isotopic forms, impacting nuclear reactions significantly.

Electron Arrangement

  • Bohr Model: Electrons arranged in ordered fashion, transitioning between energy levels.

  • Quantum Model: Electrons described by probability in shaped orbitals; principal energy levels correlate to distance from nucleus.

Relationship with Periodic Table

  • Electron configurations correlate with element properties; structured in groups (similar properties) and periods (varied properties).

  • Groups defined (1A-8A) by valence electron configurations, with distinct names for certain groups:

    • Alkali Metals, Alkaline Earth Metals, Halogens, Noble Gases.

Green Chemistry and Solar Fuels

  • Artificial photosynthesis can generate hydrogen fuel.

  • Hydrogen fuel can be utilized to produce heat and electricity through reaction with oxygen.