A.2.1 - periodic table and atomic structures

• History of atomic structure

  • Dalton: billiard ball model
  • Thomson: plum pudding model
  • Rutherford: nuclear model
  • Bohr: planetary model
  • Schrodinger: clouds of probability
• Law of Conservation of Mass

  • Mass of reactants = mass of products
  • Boyle and Lavioser
• Periodic table

  • Periods - rows
  • Groups - columns
• Periodic table groups

  • Alkali metals, Alkaline earth metals, Halogens, Noble gases
  • Reactive -> unreactive
• • Atoms
  • Protons - positive , in nucleus 
  • Electrons - negative , surrounds nucleus
  • Neutrons - neutral , in nucleus
• APEMAN

  Atomic # = protons = electrons

  Mass - Atomic # = neutrons
• Isotope - # protons ≄ # neutrons

  • If mass is different than on a periodic table, it's an isotope
  • Oxygen's most common isotope: 16O
• Energy levels

  • Electrons have energy levels
  • Closer to nucleus = lower energy
  • 1st energy level holds 2 electrons (2 8 8)
• Ions - atoms with a charge

  • Due to losing / gaining electrons
  • Due to wanting a complete valence shell (stable)
  • Valence shell 4: cation lose, anions gain