Lecture Notes: Atomic Structure and Basics

Key Concepts

• Atomic Theory Application: Understanding the composition and structure of atoms.
  • Atoms are composed of protons, neutrons, and electrons.
  • Protons and Neutrons: Found in the nucleus.
  • Electrons: Reside in orbitals outside the nucleus.

Abbreviations

• Protons:
  • p or p+ (proton, positive charge)
  • H+ (used as a proton in chemistry)
• Neutrons:
  • n or n0 (neutral, zero charge)
• Electrons:
  • e- (negative charge)

Proton Details

• Mass: 1.67272 x 10^-27 kg (approximately 1 amu)
• Charge: +1.602 x 10^-19 C (positive)
• Hydrogen Atom: One proton in the nucleus, can have 0-2 neutrons.
  • H+ indicates a hydrogen atom that lost its electron.

Neutron Details

• Mass: 1.675 x 10^-27 kg (slightly more than a proton, ~1 amu)
• Charge: Neutral (0)

Electron Details

• Mass: 9.10939 x 10^-31 kg (about 1/2000 amu)
• Charge: -1.602 x 10^-19 C (negative, written as -1)

Atomic Structure Summary

• Volume: Determined by electron cloud/orbitals.
• Mass: Concentrated in the nucleus (protons + neutrons).

Definitions

• Atom: Neutral particle (protons = electrons).
• Ion: Charged particle (protons ≠ electrons).
  • Cation: Positively charged ion (more protons).
  • Anion: Negatively charged ion (more electrons).

Elemental Notation

• Atomic Number (Z): Number of protons, defines the element.
• Mass Number (A): Protons + neutrons.
• Isotopes: Same element, different neutron numbers.
  • Example: Hydrogen isotopes (protium, deuterium, tritium)
• Elemental Symbol Notation:
  • Format:
    • E: Element symbol
    • Z: Atomic number
    • A: Mass number
    • Charge: If applicable

Molecules and Mixtures

• Atomic Mixtures: Two or more elements not chemically bonded.
• Molecular Compounds: Non-metal atoms bonded, e.g., water (H₂O).
• Mixtures: Combinations of atoms, molecules, or compounds.

Concepts of Stability and Reactions

• Nuclear Chemistry Preview:
  • Beta decay and electron capture.
  • Radioactive decay leads to more stable nuclear configurations.

Practical Examples

• Sodium Ion (Na⁺): Loses electron, becomes smaller.
• Phosphorus Ion (P³⁻): Gains electrons, has negative charge.

Visualizing Concepts

• Importance of visualizing atomic and molecular interactions for better understanding.

This summary covers the essential points from the lecture on atomic structure, elemental composition, and the behavior of atoms and ions in different chemical contexts.